Advertisement

Journal of Molecular Evolution

, Volume 53, Issue 1, pp 70–76 | Cite as

High Evolutionary Rates in Nuclear Genes of Squamates

  • Sandrine  Hughes
  • Dominique  Mouchiroud

Abstract.

We compared nonsynonymous substitution rates (Ka) of nuclear coding genes between four major groups of living sauropsids (reptiles): birds, squamates, crocodiles, and turtles. Since only 9 orthologous genes are known in all the four taxonomic groups, we searched for orthologous genes known in chicken and at least one of any representative of poikilotherm sauropsids. Thus, we analyzed three additional data sets: 28 genes identified in chicken and various squamates, 24 genes identified in chicken and crocodilians, and 20 genes identified in chicken and turtles. To compare nonsynonymous substitution rates between all lineages of sauropsids, we used the relative-rate test with human genes as the outgroup. We show that 22/28 nuclear coding genes of squamates, especially snakes (15/16), have an higher evolutionary rate than those in chicken (in mean, 30–40% faster). However, no such difference is detected between crocodiles, turtles and chicken. Higher substitution rate in squamates nuclear coding genes than in chicken, and probably than in other sauropsids, could explain some of the difficulties in resolving the molecular phylogeny of reptiles.

Key words: Reptiles — Squamates — Crocodiles — Turtles — Nuclear genes — DNA evolution — Relative rate test 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag New York Inc. 2001

Authors and Affiliations

  • Sandrine  Hughes
    • 1
  • Dominique  Mouchiroud
    • 1
  1. 1.Laboratoire de Biométrie et Biologie Évolutive UMR-CNRS 5558 — Université Claude Bernard — Lyon 1 43, bd du 11 Novembre 1918, 69622 Villeurbanne cedex, FranceFR

Personalised recommendations