What selective forces drive codon usage patterns?
Examine codon utilization patterns for genes expressed in different tissue of the same organism or in response to different stimuli. Evaluate the selective factors that might lead to differences where they are found. See Proc. Natl. Acad. Sci. 83, 8132-8136 (1986). n) Identifying primitive molecular traits. Cairns-Smith in his book, Seven Clues to the Origin of Life, concludes that the oldest components of biological systems are the least variable. Is this a fundamental principle of biochemical evolution that can guide one in seeking the origins of any biochemical system? Can one determine the biochemical characteristics of the most recent common ancestor of all life? Proc Natl Acad Sci 86:7054-8 (1989). o) Evolution of lipid membranes. Archaebacterial membranes contain glygerolipids possessing ether-linked isoprenoid hydrocarbons. Eukaryotes and other prokaryotes contain glycerolipids with ester-linked fatty acids. Both isoprenoids and fatty acids are biosynthesized from acetyl-CoA. A
