Generation Time and Genomic Evolution in Primates

Abstract

1144References 1. P. C'uatrecasas, Proc. Nat. Acad. Sci. U.S.A. 63, 450 (1969).2. T. Oka and Y. J. Topper, ibit. 68, 2066 (1971); Nature New Biol. 239, 216 (1972) Biophys. Res. Commun. 41, 1362 Lett. 12, 263 (1971); ibid. 20, 191 (1972). 7. P. Cuatrecasas, Proc. Nat. Acad. Sci. U.S. A. 69, 318 (1972); ibid., p. 1277; J. Biol. Cheni. 247, 1980 (1972). 20) January 1973. Generation Time and Genomic Evolution in PrimatesIt is widely accepted among those who study evolution at the molecular level that time is a major factor determining the degree of sequence difference among the homologous macromolecules of different species. Whether done on the globins (I), cytochromes c (2), fibrinopeptides (3), albumins (4-7), lysozymes (8), or DNA's (9, 10), such studies have generally shown a strong correlation between the degree of sequence difference and the time that has elapsed since the two species being compared last shared a common ancestor. Substantial disagreement persists, though, on the question of whether the time factor should be measured in terms of astronomical time or generation length (9-12). These conflicting hypotheses have been subjected to direct test, and we here review evidence developed in such tests which strongly supports the astronomical time hypothesis.It is important at the outset to make clear the distinction between measuring absolute and relative rates of macromolecular evolution. We believe that the failure to make that distinction has led others (9-12) unwittingly to favor the generation time hypothesis. To measure absolute rates of macromolecular evolution requires known times of divergence between living species and is thus completely dependent on a detailed and properly interpreted fossil record. The method is illustrated by the following example. If it is known that the albumins of two species A and B differ in sequence by x amino acid replacements and that the A and B lineages diverged t million years ago, the average rate of albumin evolution in this case is x/t amino acid replacements per million years of separation. Although t is sometimes known precisely, this will not be true for most absolute rate measurements. It is relatively easy The divergence times are those used in (12); thus, we do not denote a specific divergence time for the tree shrews. For our calculations we have used the relationship between generations per year [X(t)] and time in millions of years (t) given in (12).However, one of their equations, X2(t) = 0.216tr'5, is incorrect and should read X2(t) = 0.358r'"; we have used the latter in our calculations.

Molecular studies of Callithrix pygmaea (Primates, Platyrrhini) based on transferrin intronic and ND1 regions: implications for taxonomy and conservation

“…The estimated time since divergence was calculated by means of the branch lengths of the NJ trees and the method proposed by Sarich and Wilson (1973), using the estimated time of 13 million years ago (Mya) for the emergence of the tribe Callitrichini (Goodman et al, 1998).…”

Molecular Evolutionary Analysis of the Thiamine-Diphosphate-Dependent Enzyme, Transketolase

“…First we considered the rates from mouse (Mmu) and rat (Rno) transketolase. A method for comparing evolutionary rates in homologous genes is a relative rate test that does not require the knowledge of divergence times (Sarich and Wilson 1973;Wu and Li 1985). Using the human gene Hsa(ad) as a reference sequence we calculated the differences in synonymous and nonsynonymous substitutions and obtained 4.5 ± 10.62 and −0.12 ± 0.97 substitutions per 100 sites, respectively, the negative sign indicating a higher rate in Wierenga et al (1985).…”

The phylogeny of Mediterranean tortoises and their close relatives based on complete mitochondrial genome sequences from museum specimens

“…hermanni clade. We compared differences in substitution rates between members of this clade using relativerate tests (Sarich and Wilson 1973;Wu and Li 1985). In RRTree 1.1.9 (RobinsonRechavi and Huchon 2000) we compared rates in a pairwise fashion between each member of the A. horsfieldii + Indotestudo + M. tornieri + Testudo + 'T.'…”