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Eukaryogenesis, how special really?
Edited by Nancy A. Moran, University of Texas at Austin, Austin, TX, and approved March 19, 2015 (received for review January 12, 2015)
Eukaryogenesis is widely viewed as an improbable evolutionary transition uniquely affecting the evolution of life on this planet. However, scientific and popular rhetoric extolling this event as a singularity lacks rigorous evidential and statistical support. Here, we question several of the usual claims about the specialness of eukaryogenesis, focusing on both eukaryogenesis as a process and its outcome, the eukaryotic cell. We argue in favor of four ideas. First, the criteria by which we judge eukaryogenesis to have required a genuinely unlikely series of events 2 billion years in the making are being eroded by discoveries that fill in the gaps of the prokaryote:eukaryote "discontinuity." Second, eukaryogenesis confronts evolutionary theory in ways not different from other evolutionary transitions in individuality; parallel systems can be found at several hierarchical levels. Third, identifying which of several complex cellular features confer on eukaryotes a putative richer evolutionary potential remains an area of speculation: various keys to success have been proposed and rejected over the five-decade history of research in this area. Fourth, and perhaps most importantly, it is difficult and may be impossible to eliminate eukaryocentric bias from the measures by which eukaryotes as a whole are judged to have achieved greater success than prokaryotes as a whole. Overall, we question whether premises of existing theories about the uniqueness of eukaryogenesis and the greater evolutionary potential of eukaryotes have been objectively formulated and whether, despite widespread acceptance that eukaryogenesis was "special," any such notion has more than rhetorical value.
The eukaryotic cell originated by the most complex set of evolutionary changes since life began: eukaryogenesis. Their complexity and mechanistic difficulty explain why eukaryotes evolved two billion years or more after prokaryotes. To understand these changes, we must consider the cell biology of all five major kinds of cells; determine their correct phylogenetic relationships; and explain the causes, steps, and detailed mechanisms of the radical transitions between them. [Cavalier-Smith (1)]
The acquisition of mitochondria was the pivotal moment in the history of life. [Lane (2)]
Compared to prokaryotes, eukaryotic cells represent not only an alternative mode of cellular organization but one endowed with far richer evolutionary potential: only among Eukarya do we find integrated multicellular creatures that bear embryos, respond to music, and reflect on their own nature. Whatever meaning one assigns to the history of life, the advent of eukaryotic cells marked a radical and fateful transition. [Harold (3)]
In the early 1960s, Stanier et al. famously wrote that the "basic divergence in cellular structure, which separates the bacteria and blue-green algae from all other cellular organisms, represents the greatest single evolutionary discontinuity to be found in the present-day world" (4). Nowadays, a tripartite division of the living world is more popular—prokaryotes comprising Bacteria (including "blue-green algae") and Archaea. However, the sentiment remains strong that the transition between prokaryotic and eukaryotic cell types, whether by symbiogenic or archezoan schemes (5), was the single most important step in cellular evolution. The founding endosymbiosis [or syntrophic merger a la the Hydrogen Hypothesis (6)] entailed unique cellular mechanisms and had uniquely important, radical consequences for both the subsequent evolution of organismal complexity and the articulation of evolutionary theory, it is believed. The biochemist Nick Lane has written, for instance,
If the origin of the eukaryotic cell was not a bottleneck, then it was probably a genuinely unlikely sequence of events, for it happened only once. Speaking as a multicellular eukaryote, I might be biased, but I do not believe that bacteria will ever ascend the smooth ramp to sentience, or anywhere much beyond slime, here or anywhere else in the universe. No, the secret of complex life lies in the chimeric nature of the eukaryotic cell—a hopeful monster, born in an improbable merger 2000 million years ago, an event still frozen in our innermost constitution and dominating our lives today (2).
Writing for public audiences, and often even for themselves, biologists are not loath to make simplifying claims about uniqueness and importance that are rhetoric disguised as fact. Such generalizations serve purposes in the doing of science, but are often not themselves testable scientific claims and are subject to biases. Evolutionary biology may be especially vulnerable to hype, as suggested by the frequency with which revolutionary evolutionary claims in top-notch journals are debunked (7, 8). Additionally, anthropocentrism, as it grades into "zoocentrism" (9) and then "eukaryocentrism," surely remains a subtle distorter of objectivity.
Our aim here is to critique general claims about the uniqueness and special importance of eukaryogenesis, with an aim to making them more open to question and conceptual and empirical analysis. We ask (i) whether eukaryogenesis entailed such a "genuinely unlikely sequence of events" (2) as to justify belief in its uniqueness as a process, (ii) if, as is often claimed, eukaryogenesis has a problematic or unique theoretical status in evolutionary biology, (iii) what intrinsic features might have conferred on eukaryotes their presumed "richer evolutionary potential" (3), and (iv) if this greater potential might be just a presumption, an illusion reflecting eukaryocentric bias.
Was Eukaryogenesis Unique as a Process?
It is often said that eukaryotes arose only once. What must really be meant by this is that there was but one last eukaryotic common ancestor (LECA) from which all contemporary living things that we call eukaryotes descend, and that if other lineages with similar features arose independently, they are now extinct or have not been found. Often, LECA is conceptualized as a single cell, but unless it was obligately asexual [which comparative genomics suggests that it was not (10)], single species seems a better bet. Also, unless eukaryogenesis was a once-in-a-universe cataclysmic miracle, in which all eukaryote-specific features appeared simultaneously and full-blown, there were very likely many contemporaneous lineages with all or some of those features. It need not be that eukaryogenesis was so onerous that it took 2 billion years to accomplish, as Cavalier-Smith (1) maintains. As likely, we think, is that only one of many near-eukaryotic lineages survived. Notwithstanding claims about its enormous evolutionary potential, perhaps that lineage was just lucky!
Along the lineage leading to LECA, what we might choose to designate as the first eukaryotic common ancestor (FECA) (11) depends (barring that miraculous cataclysm) on which eukaryote-defining feature we take as necessary and sufficient for eukaryoteness. Nowadays, many theorists would nominate the mitochondrion as that feature. Here again we should be thinking not only of multiple contemporaneous but also reticulating lineages leading from FECA to LECA. It seems certain, for instance, that endosymbiotic gene transfer (EGT) entails the physical destruction (lysis) of the specific donor endosymbiont. Therefore, reduced endosymbiont or organellar genomes must have had slightly, and could have had substantially, different evolutionary histories than any EGT-derived nuclear genes now contributing to mitochondrial function and maintenance. Additionally, if we, in principle, accept that interspecies lateral gene transfer (LGT) was involved in the assembly of such complex prokaryotic structures as the photosynthetic apparatus (12) or type III secretion systems (13), we must also allow that the true histories of many nonmitochondrial eukaryotic cellular features are complex and reticulated, only appearing linear because of extinction and as yet poor sampling of available diversity.
For much of the last half of the last century, leading theorists would have seen the development of phagocytosis (by whatever means) as the first and perhaps most crucial event in eukaryogenesis. For instance, Stanier wrote, in 1970, "that the progressive structural evolution of the eukaryotic cell received its initial impetus from the acquisition of a novel cellular property, the capacity to perform endocytosis" (14). Lacking such a capacity, prokaryotes would be unable, it was thought, to acquire intracellular symbionts. By rights then, there should have once been "archezoa," cellular organisms with many or all of the trappings of eukaryotes, except mitochondria (15). The fact that there seem not to be such creatures surviving to this day is one (albeit not a fatal) failing of the phagocytosis-first view.
Another is the recent discovery (16, 17) that the mealybug endosymbiotic β-proteobacterium Tremblaya harbors the γ-proteobacterial endosymbiont Moranella, on which it is absolutely dependent for complementation of many of its missing genes (it retains only 120!). This finding tells us that prokaryotes can acquire other prokaryotes as endosymbionts without first developing eukaryote-like phagotrophy. No doubt, exclusively prokaryotic endosymbiosis is a very rare occurrence, but since it is the very rarity (indeed, uniqueness) of eukaryogenesis that many seek to celebrate and rationalize, Moranella provides an ironically inverted sort of support for endosymbiosis-first (symbiogenic) scenarios.
In this century, it is probably the evolution of mechanisms for importing necessary proteins into organelles that is taken as the most difficult, eukaryogenesis-limiting step. It is such import machineries that make EGT functionally feasible, even inevitable, according to the "you are what you eat" ratchet described earlier by one of us (18). Without them, functions that must be performed within organelles would require that the cognate genes be retained within the organelles. By the same token, that such machineries seem to have unique origins is taken as the strongest proof that mitochondria and plastids arose only once each. Zimorski et al. write that,
The unity of those import machineries among mitochondria and plastids, respectively, is thus widely regarded as the best evidence we have for the single origin of these organelles, as opposed to multiple independent origins in different lineages, even from endosymbionts so closely related as to be indistinguishable in phylogenies (19).
In just the last few years, however, at least one endosymbiont not genealogically related to mitochondria and plastids has been shown to (likely) have independently evolved protein transport machinery. Nowack and Grossman (20) reported that three genes encoding components of photosystem I that have been transferred to the nucleus of the (eukaryotic) amoeba Paulinella chromatophora produce cytosol-synthesized proteins that are imported back into chromatophores. These latter are cyanobacterial descendants with highly reduced genomes, which apparently first entered into endosymbiosis only some 60 Mya, long after and completely independently from (other) plastids. Whether there is some key difference between a highly dependent endosymbiont and an organelle is a definitional matter and not a scientific question answerable by experiment (21). Indeed, McCutcheon and Keeling, prefiguring our title, recently asked, "Is there really anything so special about organelles?" (22).
Less extensive and less extensively argued over but of increasing abundance and relevance are data bearing on the timing and order of the appearance among prokaryotes of precursors of structures or processes once thought to be exclusive to and universal among eukaryotes—endomembrane systems comprising the nucleus, endoplasmatic reticulum, and Golgi apparatus and a cytoskeleton involved in cellular motility, phagocytosis, and vesicular trafficking. Coincidentally, there is mounting evidence supporting something like James Lake's long discounted "eocyte hypothesis," in which the eukaryotic nucleocytoplasmic lineage emerged from within or near the Crenarchaeota rather than before any divergence within what we call Archaea (23). If this hypothesis holds up, then we might expect to find closer and closer homologs of components of the several eukaryote-specific cellular machineries [now called eukaryotic signature proteins (24)] as we explore inferred proteomes of such archaea [the group of phyla comprising Thaumarchaeota, Aigarchaeota, Crenarchaeota, and Korarchaeota (TACK)].
Indeed, we do find such homologs, as Martijn and Ettema (24) and Koonin and Yutin (25) assert in recent reviews. Martijn and Ettema (24) are so bold as to formulate what they call the "phagocytosing archaeon theory" (phAT). Starting with an (imaginary) archaeon bearing all eukaryotic signature proteins so far found in one or another of the TACK archaea, such as actin, tubulin, the ubiquitin protein modifier machinery, and several transcription and translation proteins, they envision loss of the cell wall (which does occur) and duplication of the archaeal actin, facilitating shape changes and occasional engulfing of other prokaryotes, resulting in elevated rates of LGT. None of these capacities seem impossible, although such a multiply capable creature is not known to exist now. In part to accommodate this fact, Koonin and Yutin (25) propose, similar to the phAT,
… that the archaeal ancestor of eukaryotes was a complex form, rooted deeply within the TACK superphylum, that already possessed some quintessential eukaryotic features, in particular, a cytoskeleton, and perhaps was capable of a primitive form of phagocytosis that would facilitate the engulfment of potential symbionts. This putative group of Archaea could have existed for a relatively short time before going extinct or undergoing genome streamlining, resulting in the dispersion of the eukaryome. This scenario might explain the difficulty with the identification of the archaeal ancestor of eukaryotes despite the straightforward detection of apparent ancestors to many signature eukaryotic functional systems (25).
Additional genomic exploration among the still largely uncharacterized TACK and DPANN archaea (a newly recognized monophyletic superphylum) (26) cannot but further narrow the prokaryote–eukaryote gap. One might predict a future day in which no steps (inventions or mechanisms) entailed in whatever is then the prevailing theory of eukaryogenesis are not found as homologs or reasonably matching analogs in one or another prokaryotic lineage. Still, we may never find all of them in a single surviving lineage: in any case, a patchy prokaryotic distribution of preeukaryotic features is what advocates of rampant LGT as a crucial evolutionary process should expect, as Martijn and Ettema (24) and Koonin and Yutin (25) note.
Evolutionary scenarios gain plausibility through elaboration, the filling in of steps. Elaboration directs comparative data collection, which is, for scenario building, the equivalent of experimentation in hypothesis testing. Good progress is currently being made on eukaryogenesis, as other papers in this collection report. In the end, we may still have what Lane (2) calls a "genuinely unlikely sequence of events," but there will be nothing unique or special about that: all evolutionary stories are genuinely unlikely. There is no unbiased calculus by which we can say that the appearance of subsection V cyanobacteria—which grow as filaments with differentiated heterocysts, produce cyst-like resting cells and differentiated motile trichomes (hormogonia), and show true branching—entailed fewer or simpler steps than the evolution of, say, marsupials. Given the larger population sizes of prokaryotes, their evolution stories might involve more fixations by natural selection than the stories of eukaryotes (27). Although fewer of the prokaryotic fixations would be visible or seem remarkable to multicellular eukaryotes like ourselves, cyanobacteria are possibly more highly derived (or "evolved") than marsupials. It is a matter of scale and perspective.
The combinatorial stringing together of all of the steps between LECA and Macropus rufus (the red kangaroo), Trichomonas vaginalis, or Mozart is, indeed, laughably improbable. Surely, if life's tape was rewound, none of these would recur (28). However, combinatorial improbability is how evolution works: that eukaryotes arose is not unique in its uniqueness. What might still be special about eukaryogenesis is that, whatever scenario is embraced, two evolutionary lineages enter and one emerges. Some have argued that this puts eukaryogenesis outside the purview of Darwinian theory.
Does Eukaryogenesis Have a Problematic or Unique Theoretical Status in Evolutionary Biology?
Theoretical issues that have received attention from both biologists and philosophers of biology concern the individuality (or lack thereof) of the eukaryotic cell as well as the nature of the particular evolutionary processes that gave rise to it. Is the eukaryotic cell best seen as a kind of community composed of two or three taxonomically divergent entities or as a genuine individual that can be part of an evolving population of similar things? Should the answer have an impact on biological theory?
Margulis, a champion of endosymbiotic theory, argued for the community perspective on the eukaryotic condition. Symbiotic mergers similar to eukaryogenesis, she insisted, are ubiquitous in the history of life. As a result, our understanding of evolutionary processes requires the radical revision, perhaps abandonment, of many traditional neo-Darwinian ideas. Margulis takes the issue of individuality to be central to these critiques: "The fact that 'individuals'—as the countable unities of population genetics—do not exist wreaks havoc with 'cladistics'" (29). Moreover, "[f]ailure to acknowledge the composite nature of the organisms studied invalidates entire 'fields' of study" (29).
We agree that questions about the individuality of the eukaryotic cell are important and have ramifications for our theoretical understanding of eukaryogenesis as an evolutionary process. However, in contrast to Margulis, we think that contemporary evolutionary theorizing has the resources to helpfully illuminate eukaryogenesis in terms of both process and product. What also emerges is a picture in which symbiotic mergers similar in many respects to eukaryogenesis are not entirely uncommon and can be found at hierarchical levels above that of the cell.
The starting point is to understand eukaryogenesis as an instance of a "major transition in evolution" (30, 31). Major transitions can be characterized in several ways, often in terms of the evolution of complexity or new modes of intergenerational information transfer. For our purposes, however, the most important feature of transitions is that "entities capable of independent replication before the transition can replicate only as part of a larger whole afterwards" (30). Often, this "larger whole" is conceptualized as an emergent individual. Indeed, the literature on transitions has been closely linked with that on the evolution of individuality (32 ⇓ –34).
It is uncontroversial that eukaryogenesis involved the fusion of two taxonomically distinct units to form a new type of cell. Eukaryogenesis can thus be distinguished from evolutionary transitions based on the integration of closely related units (as in the evolution of multicellularity). Queller (35) has dubbed the former kind of transition "egalitarian" and the latter kind of transition "fraternal" (35). Egalitarian alliances are
… egalitarian in the sense that both partners reproduce (although not necessarily equally). The advantage of such alliances is the bringing together of two disparate units with distinct capabilities, a combination of function, which in the new entity becomes a division of labor. The greatest barrier to such alliances may be the potential for the two parties to exploit each other, but such conflicts can be limited if there is sufficient mutual interdependence (35).
Queller here makes two important points about transitions. First, the parts of a new whole may retain some independence with respect to their ability to reproduce. Second, interdependence of parts is emphasized as a threshold that must be crossed for a new type of individual to have truly evolved. Both are what we see in the case of the eukaryotic cell. Eukaryotic cells undoubtedly exhibit many of the hallmark features of biological individuality, including spatiotemporal boundedness, indivisibility, and the integration, cooperation, and interdependence of parts. Mitochondria divide by fission, much like their bacterial ancestors. Unlike that of their free-living ancestors, however, mitochondrial replication is not autonomous; most of the proteins required are encoded in the nucleus and imported into the organelle (36). Mitochondrial replication is an evolved outcome made possible by EGT. Precisely how EGT and the resulting loss of reproductive and metabolic autonomy by the bacterial symbiont occurred is a matter of debate, but the outcome is not. All extant eukaryotic cells reproduce but also contain parts that reproduce, albeit in a way regulated by the whole. Eukaryogenesis was thus a major transition in the sense that mitochondria and their host cells "can replicate only as part of a larger whole" (30).
Godfrey-Smith (37) speaks of "Darwinian individuals" as members of "Darwinian populations," collections of entities related by descent and showing sufficient heritability of fitness-affecting variation so as to evolve by natural selection. Two things are true about eukaryotic cells. First, they are Darwinian individuals [in Godfrey-Smith's sense (37)] arising through an egalitarian transition [in Queller's (35)]. Second, the partners involved in the transition retain sufficient reproductive autonomy so as to themselves sometimes be Darwinian individuals, capable of conflict as documented in cytoplasmic male sterility (38).
Vertical transmission of mitochondria during cell replication is particularly evolutionarily significant here and underwrites the first truth. In general, vertical transmission ensures that offspring always inherit the same lineage of symbiotic partners with which their parents associate. The result is a reproductive process, in which parts of several origins are transmitted together at the creation of a new generation of eukaryote, making eukaryotic cells Darwinian individuals (39) and not communities. Vertical transmission also opens the door to "partner fidelity feedback," in which a feedback effect involving intergenerational mutual fitness-enhancing interactions between two entities can lead to the evolution of interdependence (40).
Margulis was right that eukaryogenesis poses a challenge for evolutionary theory but wrong that a suitable articulation of Darwinian individuality could not accommodate it. There is no theoretical barrier to conceptualizing and explaining the origin of a new kind of collective individual from the merging of two independent lineages. No wholesale rejection of Darwinian theorizing (broadly construed) is required, although analysis of how common reticulated patterns of ancestry and descent are at hierarchical levels above the gene may be in order.
Eukaryogenesis is not unique as an organismal merger of entities from taxonomically distinct lineages, although the tightness of integration between mitochondria and their host is probably the most derived currently known. [The mergers that are implied by Nelson-Sathi et al. (41) would, however, be even more derived or complete if these implications are born out]. Among studied exclusively prokaryotic multilineage consortia, varying levels of integration have been documented, although endosymbiosis is extremely rare (16). Nevertheless, syntrophic interactions between anaerobic methane-oxidizing archaea and sulfate-reducing bacteria have resulted in the evolution of aggregates with a measure of coordinated growth and reproduction between the partners (42). Even farther down the organismal path is the two-species bacterial consortium "Chlorochromatium aggregatum," which has been championed as a model of bacterial multilineage multicellularity (43). In this symbiosis, green sulfur bacterial epibionts (Chlorobium chlorochromatii) surround a motile β-proteobacterium (Symbiobacter mobilis). The central bacterium relies extensively on the photosynthetic products of its epibionts and has undergone extensive genome reduction (44), a mark of evolved dependence.
In eukaryotes, endosymbiosis is common, which other papers in this collection amply illustrate. P. chromatophora, as previously mentioned, harbors photosynthetic endosymbionts derived from free-living cyanobacteria. The chromatophores are vertically transmitted and partitioned to offspring equitably. There is also substantial genomic integration between host and symbiont as a result of EGT and the invention of protein import machinery. Paulinella and its symbionts are mutually interdependent, and neither can replicate independently, indicating that the symbiosis is the result of a transition similar in many respects to eukaryogenesis (21).
Intracellular endosymbiosis can also be found at the multicellular organismal level of the biological hierarchy. Bacteria frequently associate with insects in mutualistic symbioses (most commonly among insects with nutrient-poor diets). Bacterial associates provide nutritional supplementation. Pea aphids and their relationship with Buchnera aphidocola bacteria are a well-understood example of this kind of association. Buchnera reside in specialized bacteriocytes and are maternally transmitted to offspring: the aphid/Buchnera holobiont satisfies quite stringent reproductive criteria for Darwinian individuality (45). There are many other cases of insects associating with intracellular mutualistic bacteria for nutritional supplementation (46).
Broader definitions of endosymbiosis are available, moving beyond intracellular symbionts to include symbionts inside host tissue generally (46). Once this broader definition is taken on board, it becomes apparent that symbiotic alliances making up collective Darwinian individuals are also not infrequently formed between multicellular eukaryotic partners. Perhaps the most astounding case is that of the higher attine leaf cutting ants and their close association with Leucocoprinae fungi. Inside attine ant nests is a fungal garden, which constitutes the main source of nutrition for the workers of the colony. The two partners have been coevolving in a symbiotic relationship for an estimated 10 million years (47). Fertilized queens are the propagules that found new nests, and they always transport a small bit of the fungal cultivar from their nest of origin, a form of vertical transmission (48). Phylogenetic comparison between higher attines and their fungal cultivars reveals congruence in tree topology, suggesting long periods of sustained coevolution and partner fidelity feedback between specific cultivar strains and different species of ants (49).
Attine ant colonies and their associated fungal cultivars are mutually interdependent. Ant nests cannot persist without the nutritional supplementation that their members derive from the fungus. There is also evidence that the fungal strain associated with higher attines has been exclusively asexually propagated with the foundation of new ant nests (50), suggesting that the fungus requires ant participation in its own reproduction. Higher attine ants' nests, including their fungal component, are thus good candidates for Darwinian individuality at the colonial level. The relationships among the parts of these symbiotic collectives, such as endosymbiosis of fungus within the ant nest, vertical transmission of symbionts, mutual interdependence, and community-level reproduction, parallel those of the eukaryotic cell (51).
Thus, claims about both the process and product of eukaryogenesis as being unique or as challenging contemporary evolutionary theory should at least be treated with skepticism. Processes of evolution in which entities from different lineages can be bound together in the creation of new community-level reproductive individuals are not uncommon, and such symbiotic entities occur at hierarchical levels above that of the cell, sometimes among exclusively eukaryotic partners. Although there are some aspects of the eukaryotic condition that have not been documented in higher-level egalitarian alliances (e.g., gene transfer between partners), even these aspects are not unique to mitochondria and plastids, as both the Paulinella and "Chlorochromatium aggregatum" cases show (21, 44).
Following Wernegreen, we endorse a perspective according to which there are several variable "axes of integration" in endosymbiotic (or indeed, symbiotic) systems, including evolutionary stability, functional integration, cellular integration, and genomic integration, each of which can be instantiated to a greater or lesser degree (46). Eukaryogenesis is not necessarily different in kind from other symbiotic alliances that have occurred much more recently in evolutionary history, but it is a very ancient one, affected at a basic cellular level. Accordingly, it receives very high scores along each of the axes of integration. Some (but not all) of the other symbioses have lower scores along some axes. However, we suggest that there is no fundamental difference in kind between these various symbiotic alliances, just different evolutionary histories. Eukaryotes do not pose unique challenges to and do not require special treatment within evolutionary theory. What remains that might be considered special, and is the subject of the rest of this review, is eukaryotes' presumed richer evolutionary potential.
Which, If Any, Intrinsic Feature(s) Conferred on Eukaryotes Their "Far Richer Evolutionary Potential" (3)?
Once on the scene, eukaryotes are imagined to have radically altered evolution's tempo and mode. With cells structurally more complex—but at the same time, more self-similar at the cellular level—than their prokaryotic ancestors, eukaryotes radiated into a great diversity of organismal types, including complex multicellular forms with the transcendent potential to "bear embryos, respond to music, and reflect on their own nature" (3). Although few admit to frank essentialism, most would imagine that it is some (possibly single) intrinsic feature of eukaryotes (as a cell type and not a clade) that confers all of these benefits. Here, we consider some proposals as to what that intrinsic feature might be and some connections between them.
Phagocytosis and Cellular Organization.
Phagotrophic predation as an early eukaryotic or late archaeal invention [by Martijn and Ettema's phAT (24), or earlier such schemes] has several entailments, which might be taken as defining eukaryotic features. The need to maintain genes enabling the use of a variety of substrates and oxidants is reduced when metabolites are present in prey. Thus, although eukaryotes are behaviorally and anatomically diverse, prokaryotes house most of the world's repertoire of catabolic and anabolic enzymes and energy-yielding pathways. Cell motility and structural compartmentalization facilitate phagotrophic digestion and may have driven the evolution of further cellular complexity, as Cavalier-Smith (52) has exhaustively detailed. Also, as predators, larger protists will, of necessity, have smaller population sizes than their prey, with implications for fixation of additional, possibly maladaptive, complexities.
Small Populations.
Lynch (27, 53) has repeatedly emphasized that drift, triumphing over selection in small populations, can account for many of the genomic peculiarities (and large genome sizes) of eukaryotes vis à vis prokaryotes and explain other eukaryotic evolutionary "advancements". He radically questions the evolutionary benefit or selective advantage of such features.
But where is the direct supportive evidence for the assumption that complexity is rooted in adaptive processes? No existing observations support such a claim, and given the massive global dominance of unicellular species over multicellular eukaryotes, both in terms of species richness and numbers of individuals, if there is an advantage of organismal complexity, one can only marvel at the inability of natural selection to promote it. (53)
That mildly deleterious traits, some contributing to genomic complexity, can be more readily fixed in smaller populations is a prediction of population genetic theory (54). Moreover, Lynch and his colleagues, as well as one of us, have described ratchet-like processes that can create elaborate cellular machinery without improving organismal fitness (55). Whether the default interpretation of complex features is that they are adaptations and whether complexity (however defined) is itself adaptive are long-standing contentious issues in biology in general (56) that need to be readdressed in the case of eukaryogenesis.
Spliceosomal introns might well be one of the genomic feature that eukaryotes must put up with because of small population sizes (55). When these genic interruptions (found in all eukaryotes but, as yet, not in prokaryotes) were first discovered, Gilbert (57) ventured that their presence held the key to the enhanced evolutionary potential of eukaryotes. By permitting the reassortment of exonic information, they facilitate both the production of multiple and possibly differently functional proteins from a single gene ("alternative splicing") and the evolution of novel genes by recombination of exons from different genes ("exon shuffling"). Both processes have respectable evidential support, and alternative splicing is widely held to be an answer to the riddle of how humans can be (supposedly) more evolutionarily "advanced" than nematodes or fruit flies, say, while boasting hardly any more genes (58, 59). Alternative splicing seems less common in unicells (58), and therefore, it might be seen as an accidental eukaryotic "preadaptation" available to more complex multicellular descendants.
The current favorite candidate for the intrinsic eukaryotic advantage is probably energy metabolism. In a series of papers and a popular book, Lane (2) [sometimes with Martin (60)] has asserted that the enormous energy production differential that cells with mitochondria have over even the most actively respiring aerobic bacteria is what makes all of the difference. By transferring most genes other than those needed for rapidly responsive respiration to the nucleus and amplifying those few many times over (many mitochondrial genomes per organelle and many organelles per cell), eukaryotes have vastly increased the average energy available per gene expressed, protein synthesis being the cell's greatest expense. Respiring prokaryotes could have in principle done the same by amplifying a membrane-associated plasmid bearing only the relevant genes, Lane and Martin (60) admit. However, "in practice such plasmids are not found" (60), and the alternative for bacteria (whole-genome amplification) would oblige them to replicate and express hundreds of other genes superfluous to energy production. Thus,
Put another way, a eukaryotic gene commands some 200,000 times more energy than a prokaryotic gene, or at a similar energy per gene, the eukaryote could in principle support a genome 200,000 times larger. The implications for complexity can hardly be overstated. Whereas prokaryotes frequently make a start towards eukaryotic complexity, they rarely exhibit more than one complex eukaryotic trait at a time. This is because each trait has energy costs in terms of evolving and expressing novel protein families, and unless these costs can be met generously, complexity is counter-selected for energetic reasons. (60)
This argument is appealing but flawed in several ways. First, a 200,000-fold larger genome is extravagantly in excess of requirements. We humans have, at most, five times as many genes as Escherichia coli, and the eukaryotic and prokaryotic versions of slime molds (with, coincidentally, amazingly similar complex phenotypes) differ only by about 70% in gene number (12,500 for Dictyostelium discoideum and 7,316 for Myxococcus xanthus). Makarova et al. (11) calculate only a twofold increase in paralogs (gene duplication being the major route to gene number increase) on the path from FECA to LECA. Moreover, any claim that eukaryotes now need hundreds or thousands of times as much DNA, simply to control that fraction that is protein coding with greater flexibility than prokaryotes can muster, must confront the C-value paradox (the fact that comparably complex eukaryotes exhibit enormous ranges in genome size) (61).
Second, an argument for why eukaryotes can, in principle, accomplish complex evolutionary feats that prokaryotes cannot should not rest on prokaryotic failures to do so in practice. There must be a compelling and articulable reason: that something has not happened is not an explanation of why it has not. Indeed, we think that conflating what has not (or has) happened with what cannot (or must) happen is one of the flaws of many eukaryogenesis stories. Pursuing the laudable goal of determining how some contingent event played out, we persuade ourselves that it was inevitable. An analogy might be the contrast between winners at poker and roulette. Although both may celebrate, only the former has the right to boast that his success involved some intrinsic skill. We do not actually know, despite much theorizing and rhetoric, whether it is luck or skill that has given eukaryotes the advantages that we perceive them to have.
Third, and perhaps most telling with respect to the ideas of Lane (2) about energy, there are many full-fledged anaerobic eukaryotes that do not derive energy from mitochondrial respiration. The genome of the protist T. vaginalis bears an improbably many 60,000 genes (62), and Trichomonas cells show most hallmark eukaryotic features (except oxygen-respiring mitochondria). Therefore, high energy production is not, in principle, necessary to be a DNA-heavy and gene-rich eukaryote. We may find it difficult to imagine how such a cell could have evolved, incremental Darwinian step by incremental Darwinian step, from anaerobic prokaryotic antecedents, but invoking a transient aerobic intermediate does not reduce the difficulty. There is no reason to believe that evolving a new trait ["expressing novel protein families" (60)] takes more cellular energy than maintaining it.
Unique Combination of Factors.
If, indeed, eukaryotes have an intrinsic evolutionary advantage, we suspect that there is no one single feature responsible. Conferral of such advantage should have led, almost by definition, to an adaptive radiation into multiple ecological niches and increased the likelihood that diverse lineages, some lacking the full panoply of eukaryotic traits, would survive to today. The abiding mystery of LECA is that it seems to have already possessed most defining eukaryote characteristics (63). Therefore, either the adaptive radiation-generating addition was the most recent to be acquired or that advantage, if any, requires the full eukaryotic cellular phenotype. Arguments to the effect that full-fledged eukaryotes were so much more efficient at exploiting the niches that their ancestors occupied that they drove them (and other near-eukaryotic sister lineages) to extinction seem, in the context of extensive knowledge about the fine-scale mapping of microorganisms to microniches, ecologically naive.
Unquestionably, eukaryotes evolve differently in tempo and mode than do prokaryotes, if we assess this by uniform measures of structural and functional innovation at the levels of genes and their products or cellular phenotypes. However, cyanobacteria will also surely evolve differently from mycoplasmas or methanogens. What are our principled metrics for degrees of difference, and how are we sure that these are free of the sorts of eukaryocentric bias that we discuss in the next section? What is our metric for "richer evolutionary potential" (3)?
An instructive comparison, alluded to previously, is between the bacterial and protistan slime molds Myxococcus and Dictyostelium. In both genera, amino acid starvation causes individual motile cells to aggregate (in response to analogous signaling mechanisms) into fruiting bodies that differentiate, with some cells sacrificing their evolutionary futures so that their sisters (not always identical) might form spores. Fruiting bodies are structurally diverse among species and, without a microscope, prokaryotic and eukaryotic forms would be hard to tell apart on the grounds of structural complexity alone. In either, cheaters less inclined to self-sacrifice can arise (64). It is not clear that the ∼12,500 genes of Dictyostelium discoideum or any of its eukaryote-specific cell structures give it an advantage over Myxococcus xanthus, with ∼7,500 genes (and no eukaryotic cell structures). Although some might demur that Myxococcus is an unusually sophisticated (and large-genomed) prokaryote, the point is not that prokaryotes routinely evolve eukaryote-level complexity but that they sometimes can. To the objection that eukaryotic slime molds still do not "respond to music, or reflect on their own natures" (3), we would counter that D. discoideum and its congeners are, nevertheless, likely well above the eukaryotic average in complexity of form and behavior. Most eukaryotes live unicellular lives.
Is the Evolutionary Advantage of Eukaryotes over Prokaryotes in Fact Illusory?
Perhaps before the question, "What feature(s) confer on eukaryotes their evolutionary advantage?" should have been the question, "Is there such an advantage?" Although Lane may have been facetious when he wrote, "Speaking as a multicellular eukaryote, I might be biased …" (2), we take the possibility of eukaryocentrism seriously. Despite the efforts of Gould (9, 28) and others, biologists may still be unconsciously predisposed to a sort of biological progressivism. We may see eukaryotes as possessing, to a greater degree than prokaryotes, "advanced" traits that we value—in particular, structural complexity and diversity—and then frame how we think about such very difficult-to-define traits from a eukaryotic perspective. Although differently motivated and of less social consequence, eukaryocentrism is comparable with that eurocentrism in which the preeminence of the West is interpreted as reflecting some intrinsic racial or cultural superiority rather than mere historical contingency coupled with metrics of success that inevitably make Europe look good. In this section, we name and explore potential eukaryocentric biases.
Statistical Eukaryocentrism.
Of multicellularity, widely hailed as an achievement enabled by eukaryogenesis, Lynch writes,
Complex multicellularity has only arisen twice, once in animals and once in vascular plants. One might add fungi to the list, although the number of fungal cell types is not large, and there is some question as to whether multicellularity was ancestral to the phylogenetic group that contains animals, fungi, and slime molds. In any event, the probability that two or three origins of multicellularity simply arose by chance within eukaryotes as opposed to prokaryotes is somewhere on the order of 1/4–1/2, well below the general standards of statistical validity. Of course, many other eukaryotes are capable of producing a few different cell types, but the same is true for prokaryotes, some of which produce radically different cell morphologies. (53)
Many will, of course, disagree on how often multicellularity or "complex multicellularity" (53) has evolved, how either should be defined, and indeed, whether prokaryotes have not, in fact, evolved simpler forms of multicellularity more often (65). There is no comparability in definitions of taxa at any rank (66) that would allow quantitative comparisons of frequency. An even more ambitious comparative analysis of "complexity" or realized "evolutionary potential" designed to show that eukaryotes fall far outside any normal distribution would surely be even more problematic given unavoidable biases at both organismal and genomic levels. That truly complex multicellularity is an exclusively eukaryotic achievement is unquestionably true. That it could not have been otherwise is speculation bolstered by the false belief that what has happened must have happened.
Organismal Eukaryocentrism.
Of course, a human is in many ways more complex an organism than a single E. coli cell, and to understand the former is, by far, the more daunting task. However, perhaps this comparison is not the right one. Shapiro (67) has long held that it is the microbial colony and not the solitary cell on which biologists should focus their attention. A more inclusive—multispecies—organized entity would be the biofilm (68). Indeed, some current thinking in microbiomics would have us look at microbial communities with their complex patterns of shared metabolites and (over a longer time frame) shared genes as semiorganized and extraordinarily complex biological entities (69), forming, in some cases, holobionts with their hosts. In such a perspective, prokaryotes collectively will, of course, seem different from those few large multicellular eukaryotes that have preoccupied biologists and philosophers of biology as long as there have been either. However, it is not easy to say which is the more advanced or "endowed with far richer evolutionary potential" (3). Where is the commensurability between metabolic and morphological innovation?
Genomic Eukaryocentrism.
Maynard Smith and Szathmáry (30), not unlike others, entertained a genomic measure of complexity, noting in its favor a general increase in DNA content from prokaryotes to protists to multicellular animals and plants. Although there is some roughly similar correlation in the number of protein coding sequences, most differences in genome size reflect transposable elements and noncoding intergenic spacers. Accepting (for argument only) that this material is regulatory in nature, we might still ask whether its possession is an evolutionary advancement, enabling greater phenotypic complexity. Some theorists have argued that the eukaryotic nucleus is the more primitive, burdened with inefficiencies left over from a rather messy origin of cellular life (70). Others, as we noted earlier, see it as replete with maladaptive genomic accumulations, which may or may not affect regulation of gene expression (27, 53, 61).
There is no reason to believe that unicellular protists with large genomes regulate the expression of their genes more efficiently or with greater flexibility than do prokaryotes with much less DNA. In fact, because of their more rapid generation times and larger population sizes, we might expect prokaryotes to have more exquisitely refined regulatory systems, more selection per base pair as it were—a sort of historical complexity, alluded to above in our cyanobacteria vs. marsupial comparison. We are left then with the evolutionary potential of excess eukaryotic DNA and its ability to be co-opted into function, which might well impart a different tempo and mode to eukaryotic evolution. However, we would surely be hard pressed to show that co-optation is a more effective route to evolutionary innovation than LGT. Indeed, if LGT is fully integrated into our understanding of genomic complexity, then it is perhaps the full E. coli pangenome, soon to be if not already exceeding in number of coding sequences the human genome, that should be compared with the latter. Conceivably, its pangenome (especially if including rarer interspecific transfers) gives this single bacterial "species" a far greater range of metabolic innovation than that shown by all eukaryotes, a defensible alternative metric of evolutionary potential.
A common move in philosophy of biology is into pluralism, which in this context would be the admission that there are several ways of conceptualizing eukaryogenesis, each with its advantages but none having an exclusive claim on truth. From our perspectives as large multicellular eukaryotes able to reflect on our own natures, it is not wrong to see eukaryogenesis as a signal event. However, this is not the only justifiable perspective. Sentiments such as those quoted at the beginning of this essay, if taken as objective, mislead us into thinking that it is.
It is easy to problematize any scientific statement by asking, "What do you mean by X?", with X being one of its terms. Mere semantic quibbling is the sort of thing that can give philosophy a bad name, and we hope to have accomplished more than that here. The eukaryogenesis story as usually told (and exemplified in our epigraphs) is a sort of metascientific narrative, invaluable in motivating and positioning new research activities of all sorts and organizing existing bodies of knowledge in our minds and our textbooks. However, it is as much rhetoric as fact, and the public, not to mention biologists themselves, may often conflate the two. Our analysis has had four arguments.
i) The criteria by which we judge eukaryogenesis to have required a "genuinely unlikely series of events" (2) 2 billion years in the making are gradually being eroded by discoveries (of other symbioses and archaeal features) that fill in the gaps of the prokaryote:eukaryote "discontinuity" (4). Scenarios embracing LGT and invoking transient populations of archezoa-like ancestors are increasingly appealing.
ii) Eukaryogenesis confronts evolutionary theory in a way not different from other egalitarian transitions; parallel systems can be found at several hierarchical levels. In eukaryogenesis, the product of fusion and integration is, in the end, almost back to its starting point as a cellular reproducer, because one partner has nearly completely lost its Darwinian individuality, as discussed by Godfrey-Smith (71) elsewhere in this collection. Mitochondria are still reproducers, albeit heavily scaffolded—but that fact does not make them different from transposable elements, which are not usually considered to be coeffectors of a major transition. It is thus at least possible to deflate the "majorness" of eukaryogenesis as a transition.
iii) Identifying which of several complex cellular features confers on eukaryotes a "far richer evolutionary potential" (3) remains an area of unbridled speculation, in which various keys to success have been proposed and rejected over the five-decade history of research in this area. Several prokaryotic lineages have arguably achieved an organizational complexity greater than that of the average eukaryotic lineage without benefit of these particular features (for which a selective benefit has not been shown).
iv) The fact that eukaryotes have, indeed, the "far richer evolutionary potential" (3) is perhaps the most celebrated element of eukaryogenesis stories but the most easily criticized. It is difficult and may be impossible to eliminate eukaryocentric bias from the measures by which eukaryotes as a whole are judged to have achieved greater success than prokaryotes as a whole. The ways in which we define complexity, organisms, and genomes all privilege eukaryotes. Also, if eukaryotes have indeed triumphed by some purely objective measure, we have not eliminated the null hypothesis that this was caused by chance.
There are many useful ways of understanding evolution, and their articulations can be intellectually valuable and experimentally fruitful. We advocate a more self-conscious pluralism that would require not that we stop telling eukaryogenesis stories but that we do recognize them for what they are. We do not claim to know whether there is any best story, any theory by which the apparent differential success of eukaryotes can be objectively probed and causally rationalized. What we have questioned here is whether premises of existing theories have been objectively formulated and whether, despite widespread acceptance that eukaryogenesis was "special," any such notion has more than rhetorical value.
We thank the Natural Sciences and Engineering Research Council of Canada for support and Matthew Brown, Tyler Brunet, Carlos Mariscal, Gordon McOuat, Letitia Meynell, Maureen O'Malley, Andrew Roger, Tom Williams, and two anonymous referees for suggestions and comments.
- ↵ 1To whom correspondence should be addressed. Email: ford{at}dal.ca.
Author contributions: A.B. and W.F.D. wrote the paper.
The authors declare no conflict of interest.
This paper results from the Arthur M. Sackler Colloquium of the National Academy of Sciences, "Symbioses Becoming Permanent: The Origins and Evolutionary Trajectories of Organelles," held October 15–17, 2014, at the Arnold and Mabel Beckman Center of the National Academies of Sciences and Engineering in Irvine, CA. The complete program and video recordings of most presentations are available on the NAS website at www.nasonline.org/Symbioses.
This article is a PNAS Direct Submission.
- Cavalier-Smith T
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- Was Eukaryogenesis Unique as a Process?
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Choosing the Toyota painted body side molding is a more important part of the car selection process than most people realize. The right color can bring out the best in the car model and even be a reflection of the driver's choices and personality. But it can also be important for practical purposes. Since you plan on owning this car for a long time, you might as well choose a color that will make certain parts of driving a bit easier for yourself. A lot of it can hinge on both personal preference and where you live.
How Long Are You Outside?
If you lack a roof or garage for your living place, then you will get hit with plenty of sun. Car paint can get damaged with excessive exposure to solar rays, so getting certain paint jobs means you do have to take additional effort to cover your ride up. You could also select a color like white which doesn't really fade when exposed to sun for so long. You just need to think about how much cover you have at your own job and the roofs you have at your house or apartment.
How Distinct Do You Want it?
You'll often see some common colors on the road like black and white. While some of these are intentional for what you have to deal with in your environment, it may not be a bad idea to go for something that helps you stand out more. It makes it easier to identify in case you get lost in a parking lot or you have to go and pick someone up. You'll be surprised how much minutes you could shave off by simply having a vehicle that's more identifiable for you. At the same time, going for a more common color may help you blend in and not attract the attention of the wrong people.
How much do you want the dirt hidden?
You're inevitably going to get dirt, mud and gravel all over your car that could damage your Toyota painted body side molding. It is present on certain colors more than other ones, which doesn't leave the best impression with others and might lead you to spend more money on cleaning supplies and car washes. This one's also a bit more subjective to the environments you drive more in. Drivers that often go through rural roads may not want a car that's obviously been through plenty of dirt. It makes it awkward when they go outside into the city and have a filthy car next to some of the nicer vehicles.

subset: commoncrawl


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"The Three-Body Problem" is the first novel of the "Remembrance of Earth's Past" trilogy. A best-seller science fiction reading in its native China and very popular in the US. The book tells the story about Ye, a Chinese astrophysicist who tries to stop a mysterious global catastrophe that may have extraterrestrial origins. It offers a very different sort of plot than the usual space opera or whatever, but what impressed me the most was the obviously critical stance towards speaking about the cultural revolution in China, and thereby it might be an excellent insight into Chinese culture.
On the other hand, characters are a bit dull and none of them is convincing. The entire plot also has its ups and downs. Sometimes I was feeling pulled in, and other times I was looking forward to the next chapters.
If you like world building and big ideas read it, however, I won't be going on to book 2.
Just a quick remark why I have picked the book up as it does not cover any business related topic. The truth is that the book was on the short least of the best reading recommended by Mark Zuckerberg. I knew it was a science fiction novel but anyway I hoped to relate it somehow to the business context.
The Three-Body Problem
by Cixin Liu
Final rating:
Book details:
Size: 400 pages
Published: 2014
Other information and reviews of this book on Goodreads: https://www.goodreads.com/book/show/20518872-the-three-body-problem
Other useful links:
Cixin Liu on Wikipedia: https://en.wikipedia.org/wiki/Liu_Cixin
Remembrance of Earth's Past series: https://en.wikipedia.org/wiki/Remembrance_of_Earth%27s_Past
Other book about the future of technology and its impact on our daily life: Life 3.0 by Max Tegmark


text:
The Tips You Need to Remember When Shopping For the Best Pushchair
These days, there are various manufacturers selling high quality pushchairs on the market, therefore, it is not a simple task deciding one the most appropriate pushchair for your baby if you are unsure what you need to look for. If you are going to have a baby for the first time, then, this might be the first time you will need to buy a pushchair and there is a good possibility that you will feel confused given that there are a lot of brands as well as styles available. With the intention of making this process a little easier for you, there are some factors that you have to take into account when choosing the most appropriate pushchair for your baby.
To start with, make sure that you will consider functionality when you are choosing the right pushchair. You have to consider the manner you travel, when you will be using it, and where you will use it. If you are going on a vacation with your baby that is why you need to buy a pushchair, a lightweight pushchair is perfect for your needs, then again, you have to choose the pushchair with the complete travel system if you need to make use of it each day.
After that, it is also vital that you will determine what your budget will be. Obviously, your budget plays a vital role in your decision for the reason that this will help you identify the brands your budget can truly afford. You may want to choose those designer brands which are pricey or perhaps, you are looking for affordable pushchairs that are of good quality. It is highly suggested that you search around so that you can find some sales and bargains, especially if you are already considering a certain brand or manufacturer. If you are going to research comprehensively, there is a good chance that you will obtain the perfect pushchair that can last for many years, and in the event that you will have one more baby, he or she can use it as well.
It is also essential that you will think about the weight of the pushchair you are going to purchase. You need to determine if you are strong enough to lift and also carry the pushcart without help. It is essential as well that you can weigh up if you are always using public transport or if you are always using your own car. Do you have stairs in your home and you will need to bring the pushchair up and down regularly? Keep in mind, apart from the weight of the pushchair you will choose, there is a need for you to also think about the weight of your baby.
3 Gear Tips from Someone With Experience


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Weeden 3
Quite possibly my oldest Weeden, this a Weeden 3. These were manufactured from
1894 to 1940. Very interesting construction, the whole engine sits on top of the boiler
and uses a quarter turn to locate. The boiler is brass but the firebox is steel. Missing
it's burner, smokestack, safety valve weight and whistle top.
Back to American Engines Main Page
Back to Steam Main Page


text:
Saville Kushner
Saville Kushner is professor of Public Evaluation at the university of the West of England, Bristol. Between 2005 and 2007 he served as UNICEF regional officer for monitoring and evaluation in the Latin America/Caribbean Region. He is currently director of the Centre for Research in Education and Democracy


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Thursday am: Bit of a scramble this morning as I did my normal stunt of setting my alarm an hour adrift (got the time zone round my ear again) and having to belt around the corner to the CBRE apartment to a seminar on stadium-led regeneration sponsored by BURA and - of course - CB Richard Ellis.
Rather stylish to be late for a seminar that you are hosting and chairing, but hey!
The wonderful Charlotte Doyle of CB was hopping from foot to foot but she forgave me as soon as we got the show on the road. I think it's safe to say we hit the ground running (just as well really, there was no "Plan B") and with a glittery panel and an audience stuffed full of hitters (not bad for the third morning of MIPIM) we had a roaring success on our hands. Finished up on time and on budget at 10am and off for a bit of brekky with Brent before going up to the London Stand to retrieve my phone which I had left in the Harbour Bar (another stylish moment).
And all this before rocking up to a rather excellent seminar on Croydon for a glass of champers and a bit of a sit down! Whew! Soon be over! Next week this will all be a dream.


text:
Definition of vicissitude
1a : the quality or state of being changeable : mutability
b : natural change or mutation visible in nature or in human affairs
2a : a favorable or unfavorable event or situation that occurs by chance : a fluctuation of state or condition the vicissitudes of daily life
b : a difficulty or hardship attendant on a way of life, a career, or a course of action and usually beyond one's control
c : alternating change : succession
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Isan Elba Is Not Pleased That Dad Idris Was Chosen As Sexiest Man Alive: "It's Definitely A Topic Around School"
While Idris Elba being selected as PEOPLE's Sexiest Man Alive was a no-brainer choice to many, if not a delayed honor for the British actor, there was one person who was genuinely shocked that he was given such a title this year: Isan Elba.
The 16-year-old daughter of The Mountain Between Us star, who was announced as the 2019 Golden Globe Ambassador on Wednesday, revealed that she was excited to find out who the magazine had chosen until she found out they crowned her dad. And he didn't tell her. She found out on social medial like everyone else.
"Actually, I was on Instagram. PEOPLE said, 'Oh, we're announcing the Sexiest Man Alive,' and I was like, 'Oh yes, can't wait,'" she told PEOPLE. "I wake up in the morning and it's my dad. I was like, 'This is not what I was expecting. This is not very fun.'"
She told the magazine that her dad was very proud of the title, which hilariously made things worse for the teen.
"When I called him the day after, not even about it, he was like, 'Do you have anything to say to me?'" she said. "And I said, 'No, I don't think so.' Then he said, 'I'm the Sexiest Man Alive.' I was like, 'Oh, yeah. That. That thing. Uh, okay, cool. You're welcome."
And she can't get away from it, unfortunately. When asked if she has poked fun at him about it, she shared that it's actually classmates at her school that have gone out of their way to remind her about it when Idris is too busy to rub it in further.
"It's definitely a topic around school, so I'm the one being teased about it," she said. "It's a joking kind of way, but it gets awkward sometimes."
But who knows? Very soon, Isan could be on someone's Hollywood list, because as mentioned, the teen was made into the Golden Globes "ambassador" for next year's awards ceremony. If you'll recall, it used to be titled "Miss Golden Globe," but the name has been changed in order to make the role more inclusive and gender neutral. The honor is given to the children of famous names, and during the show, the young person hands out trophies to the winners and helps them find their way off stage. However, this year, they're also allowing the chosen ambassador to do some philanthropic work, bringing awareness to an issue of their choice. Isan is excited to be the 2019 Golden Globe Ambassador, and to speak on a topic important to her as well: mental health.
"I've always been a lover [sic] TV and movies and I dream to be in the industry one day," she said during her speech. "I'm really honored to have this position and be able to talk about things that, issues that I care about such as mental health, expression among African Americans, and my peers in particular. There's a perceived stigma and I've seen my friends struggle with it."
She should do great at the 76th annual Golden Globe Awards, which air on Jan. 6 on NBC. Isan has been a mainstay on red carpets and in front of cameras since her dad first introduced her at the 2007 premiere of Tyler Perry's Daddy's Little Girls.


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Golf Looking Good!
We think golf can be cool and look good to boot!
And it doesn't have to be some bird with half a golf swing getting her tits out...
Here's what we mean!
Arnold Palmer
Slick hair, a fag on the go, cool polo, Popeye forearms and looks like he doesn't give a fuck.
Arnold is the original style icon that brought the game to the masses and made it look good!
Susana Benavides
When you think of Bolivian exports and golf you'd probably be thinking about Dustin Johnson but this one is even better.
Susana plays on the your below LPGA and the cynics among you will probably say she will just be another Paige Spiranac and be more famous for her extra-curricular.
Could be worse!
Justin Timerlake (And Jessica Biel)
With his NSync days way behind him Timberlake has carved out a little bit of a credibility for himself.
Everyone loved a bit of 'Sexy Back' (you can admit it!) mixed with a couple of decent acting roles in films such as 'The Social Network' (admittedly in between a load of crap!)
One thing you can't argue is he's a good looking chap and we quite like his RLX polo here at Pebble. Jessica Biel ain't too bad either!
Jessica Alba
If you're tired of all the blonde bimbos who've broke 80 a few times and are now models or are Insta-famous then Jessica Alba is the perfect tonic.
Absolutely stunning and combines looking hot, stylish and classy on the course!
We're in love!
Sean Connery
You don't get much cooler than James Bond. Then you get Sean Connery As James Bond!
Here Connery is leaving his London basement flat with a set of blades and some turnups... how has golf somehow managed not to be cool with stuff like this?!
Rickie Folwer (and friends!)
You can try your best not to like Rickie Fowler but at the end of the day it proves pretty tough.
The realisation occurs that if you were young, good looking, rich and ridiculously talented you'd be just like him... to be honest we think we'd be absolute nobs!
Severiano Ballesteros
For all the legendary shots, incredible escapes and swishing and swooshing Seve was an incredibly handsome chap with style to boot.
The polo he is rocking here in the early 70s would go down a treat today in 2016. Just a pity we don't have 1% of the great man's talent or those eyebrows!
Paulina Gretsky
If we were Dustin Johnson we'd ban Paulina from the course. How on earth can a human man concentrate on six foot putts when she is walking about being a 10?!
Also he's got the distraction of every lad (pictured below) within the property perving on her!
Alex Turner of Arctic Monkeys
Continuing the James Bond theme of earlier Alex Turner rocks Gucci loafers in a bunker here before popping a decent looking shot out then blowing out some smoke.
Cool. As. Fuck.
I'm the Managing Editor at The Club. I like putting and Rioja. I dislike my low slice.


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Tiffosi is a brand loyal to the authentic spirit of Denim distinguished by innovation and maximum comfort coupled with fashion trends.
This commitment to innovation is reflected in a vast diversity of technical jeans and the constant improvement and variety of special and specific fits designed for each body.
The superior quality of materials, originality and attention to detail are all part of Tiffosi's DNA as well as the inescapable concern of turning a pair of jeans into a distinctive and special piece of clothing.
Offering the trendiest apparel at unbeatable prices across a varied set of categories: Men's, Women's, and Kid's. Tiffosi is taking Europe by storm giving the masses a real taste of fast fashion.


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Pro Bloom is immune and digestive support for pro ball-fetchers and yarn-swatters. It's our own all-natural goat's milk formula with a whopping 5 billion active probiotics and digestive enzymes, so it's good for your pet and their gut. Pro Bloom can be poured onto kibble, used to hydrate The Honest Kitchen food, or served on its own as a deliciously nutritious drink that doesn't come with any nasty pesticides or growth hormones. Perfect as a bedtime beverage!
Honest Kitchen Instant Goat Milk with Probiotics Supplies
dehydrated goats milk, dried aspergillus oryzae fermentation product, dried aspergillus niger product, dried trichoderma reesei fermentation product, dried pineapple fermentation product, dried lactobacillus casei fermentation product, dried lactobacillus acidophilus fermentation product, dried lactobacillus rhamnosus fermentation product, bacillus coagulans fermentation product
Honest Kitchen
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Honest Kitchen
We think (wo)man's best friend deserves wholesome food that's worthy of that title. We make honest meals from real, wholesome ingredients you'd find in a health food store. It's people food, made especially for pets.
an honest comparison
We know there are lots of different options when it comes to pet food purveyors. The Honest Kitchen isn't like any of them! If you're looking for a food that's all natural, made in the USA, 100% human grade, super healthy, minimally processed, with no GMO ingredients, nothing from China and tastes great too – you've come to the right place!
food that makes a difference
All pets benefit from eating a whole food diet, but we'd love to share some really amazing results about pets who saw improvement with tummy issues, itchy skin, and regaining an overall 'pep-in-their-step' in our foods.
the health benefits speak - and roll over - for themselves
When we eat well, we feel well. And the same goes for our pets. Itching, scratching, appetite woes, upset tummies and more, can all be linked to problems with food. Switching away from highly processed pet food to minimally processed, vibrant whole foods from The Honest Kitchen may be just what the doctor — or veterinarian — ordered.
higher energy levels
We've noticed we have loads more energy when we pack a homemade soup or cold pressed juice for lunch, instead of grabbing something greasy from a food truck. It's true for pups and kitties too when they eat minimally processed, whole foods. 79% of pets enjoyed increased energy levels after switching to our foods!
healthy bodyweight
Just like people, pets can end up at an unhealthy bodyweight when they eat too many refined carbohydrates, salt or processed ingredients. Clean single-source proteins and balanced healthy fats in our recipes make for a lean, keen racing-machine physique in practically no time. 60% of pets with weight problems saw in improvement after switching to our foods.
silkier coat and skin
Goodness going in equals a vibrant, outward glow. The skin and coat (and even the state of the ears) are one of the best ways to get a glimpse of your pup or kitty's inner health. Since food's a key pillar of total health and wellbeing, lackluster fur and irritated ears might mean a change in diet's called for.
78% of skin and coat problems improved when pets changed to our wholesome fare.
better digestion
Tummy troubles can be a rather frustrating (and slightly embarrassing) pet health issue. Stopped up, soft-serve or smelly bottom-fumes can be signs that something in the food isn't agreeing with them. Healthy whole food goodness, antioxidants, soluble fiber, (and a strict absence of cheap fillers and tough-to-digest by-products) can help get the tail end back on the straight and narrow.
80% of pet's digestive problems improved or resolved when their owners chose our healthy fare instead of old-fashioned kibble and cans.
dehydrated pet food 101
Preserving food by dehydration is one of the oldest and most efficient methods of food processing. We've taken this time-tested method and used it to create a healthier type of pet food with more nutritional bang for your hard earned buck.
Our dehydration process gently removes the moisture from our whole food ingredients, but still maintains all of the nice vitamins and minerals that we get by using real fruits, veggies and lean meats.
Check out our green beans to the left - before and after dehydration. They are still green, maintaining all the valuable phytonutrients important for pet health!
we put our product where our mouth is.
We taste-test every single ingredient that goes into our pet foods, to make sure it's to snuff. We've also got a man called Jerry, who's based at our co-packer full time, keeping an eagle eye on food safety and quality. He also does the odd taste test of his own, as our products are being blended.
honesty starts at the source
We source our ingredients from around the world and we've worked with many of the same suppliers since we first began in 2002. It's important to us to have long-standing relationships with producers we know and trust, so we can throw a brick through their window if something's not quite right, and buy them a pint when everything's as beautiful as they've promised. We never use any ingredients at all from China. Also, we've never actually had to throw a brick through any of our suppliers' windows.
how we walk our talk
Did you know The Honest Kitchen has a letter of No Objection from the FDA, to label our foods Human Grade? Our entire supply chain and production process have been reviewed by the FDA on two separate occasions, to earn us this distinction. Human Grade means 'food grade', 'edible', or fit for human consumption. For us, it's a line in the sand about the quality and integrity of the finished products we send out the door.
We blend our healthy pet food in a human food facility that makes things like breakfast cereal and bakery mixes. So, we abide by the same strict standards for safety, cleanliness, record-keeping and overall quality as the place that whips up your favorite cookie dough.
is all pet food human-grade?
Our recipes also meet the nutritional levels established by AAFCO (The Association of American Feed Control Officials), which is the legal way of saying, it's just like the healthy whole food you eat, but formulated especially for pets.
Some companies use a few 'human grade' ingredients, but their processing may not take place in a human food facility, so their products lose their legal human grade status. Old-fashioned pet food like kibble and canned food is 'feed grade', which means it might include not-so-tasty by-products, chemicals, fillers and other ingredients that have been condemned as unfit for human consumption (like dying, diseased, disabled or deceased animals). We wouldn't choose that for our human family, and we don't think our animal friends deserve it either.
we're passionate foodies who absolutely love animals too.
We're a pretty picky bunch too (our suppliers say our uncompromising standards are even more demanding than most of the human food companies they work with). We only make products that we're excited to feed to our own cats and dogs, that they're excited to eat, and that make a meaningful, positive difference in their lives. Anything less wouldn't be worth all the bother.


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Staff Vacancies
The Chief Executive Officer of The Donaldson's Trust, Linlithgow, invites suitably qualified applicants to apply for the post(s) of:
There are currently no vacancies.
The Donaldson Trust welcomes applications from all sections of the community, irrespective of age, race, gender, sexual orientation or disability.
Should you have any recruitment queries, please contact Human Resources:
01506 841900


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Tags: NFC
Today we are going to start our new video series "News from our R&D Lab". In these videos we want to show case some of the new technologies and interesting projects our engineering team is working on. We are happy to share some knowledge that can be useful to other developers around the world. Hopefully, our current and future customers will appreciate it as well.
Today our Technical Lead is going to introduce Near Field Communication (NFC) – is a set of standards for smartphones and similar devices to establish radio communication with each other by touching them together. Our developers often use this technology when creating applications on different platforms.
Let us know what you think. We would love to hear some feedback from the community :).


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