Heat shock proteins are amongst the most evolutionarily conserved of proteins. It is believed that the heterochronic pathway represents an evolutionarily conserved predecessor to circadian clocks. G6PD is negatively regulated by acetylation on lysine 403 (Lys403), an evolutionarily conserved residue. It is difficult to match evolutionarily related proteins in distantly related species. Henikoff constructed these matrices using multiple alignments of evolutionarily divergent proteins. This type of rational design involves reciprocal evolutionary changes at evolutionarily interacting loci. BLOSUM matrices are used to score alignments between evolutionarily divergent protein sequences. Some authors regard these subfamilies as two evolutionarily distinct families. These satiation and alternation behaviors are evolutionarily adaptive. Biophysical CCMs are more evolutionarily ancient than biochemical CCMs. Colipase is also a family of evolutionarily related proteins. The genetic divergence of Borneo elephants warrants their recognition as a separate Evolutionarily Significant Unit. Mathematical models describe how signalling can contribute to an evolutionarily stable strategy. Thiolases are a family of evolutionarily related enzymes. Flies may have been among the evolutionarily earliest pollinators responsible for early plant pollination.