Pheromones are used from basic unicellular prokaryotes to complex multicellular eukaryotes. T4 proved to be orthologs for genes essential for recombination in prokaryotes, eukaryotes and archaea. DNA usually occurs as linear chromosomes in eukaryotes, and circular chromosomes in prokaryotes. Some differences exist between eukaryotes and prokaryotes. Argonaute proteins are a family of proteins found in prokaryotes and eukaryotes. Okazaki fragments are present in both prokaryotes and eukaryotes. DNA is found as linear chromosomes in eukaryotes, and circular chromosomes in prokaryotes. Bacteria and Archaea are two domains of prokaryotes. They are found ubiquitously in both eukaryotes and prokaryotes. Many other thermosensory mechanisms exist in both prokaryotes and eukaryotes. Actin-like proteins are actin in eukaryotes and MreB, FtsA in prokaryotes. The mechanism of translation initiation differs in prokaryotes and eukaryotes. Another difference between eukaryotes and prokaryotes is mRNA transport. They are found in both prokaryotes and eukaryotes. Puromycin is selective for either prokaryotes or eukaryotes.