Table 1

Estimates of K s, the synonymous divergence; M′ and U′, genomic amino acid and deleterious mutation rates, respectively, per year; andM and U, genomic amino acid and deleterious mutation rates, respectively, per generation. We assume 80,000 genes, averaging 1500 bp in length, for vertebrates (34) and 13,600 genes, averaging 1770 bp in length, for insects (20).

SpeciesNumber of genesDivergence time (My) (reference)Generation time (years)*Ks(SE)M′U′MU
Human/chimpanzee63 6  (30)250.0179 (0.0021)0.250.126.33.0
Macaque/New World monkey2840  (31)110.147  (0.014)0.310.183.41.9
Sheep/cow5025  (31)60.0677 (0.0045)0.230.151.40.90
Dog/cat3538  (31)40.240  (0.017)0.540.402.21.6
Chicken/old world quail2834 20.120  (0.013)0.300.250.600.49
Mouse/rat42313  (13)0.50.179  (0.003)1.20.990.590.50
D. picticornis/D. silvestris4 3.7  (32)0.20.101  (0.029)0.470.350.0950.071
D. melanogaster/D. simulans42 2.5  (33)0.10.100  (0.008)0.700.580.0700.058
D. melanogaster/D. pseudoobscura2935  (33)0.10.937  (0.072)0.750.700.0750.070
  • * See suplementary data at Science Online (35).

  • Assumes that the divergence ofAnseriformes-Galliformes occurred in the late Cretaceous [∼75 My ago (31)], and uses this to calibrate a local molecular clock, assuming a linear relationship between DNA melting point (36) and date of divergence.

  • Drosophila picticornis/D. silvestris are Hawaiian Drosophila. For D. melanogaster/D. pseudoobscura, the values of M andU are corrected for variation among genes in codon bias [see (11)].