Evolutionary strata on the chicken Z chromosome: implications for sex chromosome evolution - PubMed (original) (raw)

Evolutionary strata on the chicken Z chromosome: implications for sex chromosome evolution

Lori-Jayne Lawson Handley et al. Genetics. 2004 May.

Abstract

The human X chromosome exhibits four "evolutionary strata," interpreted to represent distinct steps in the process whereby recombination became arrested between the proto X and proto Y. To test if this is a general feature of sex chromosome evolution, we studied the Z-W sex chromosomes of birds, which have female rather than male heterogamety and evolved from a different autosome pair than the mammalian X and Y. Here we analyze all five known gametologous Z-W gene pairs to investigate the "strata" hypothesis in birds. Comparisons of the rates of synonymous substitution and intronic divergence between Z and W gametologs reveal the presence of at least two evolutionary strata spread over the p and q arms of the chicken Z chromosome. A phylogenetic analysis of intronic sequence data from different avian lineages indicates that Z-W recombination ceased in the oldest stratum (on Zq; CHD1Z, HINTZ, and SPINZ) 102-170 million years ago (MYA), before the split of the Neoaves and Eoaves. However, recombination continued in the second stratum (on Zp; UBAP2Z and ATP5A1Z) until after the divergence of extant avian orders, with Z and W diverging 58-85 MYA. Our data suggest that progressive and stepwise cessation of recombination is a general feature behind sex chromosome evolution.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Proc Natl Acad Sci U S A. 1998 Jul 7;95(14):8147-52 - PubMed
    1. Genetics. 2000 Aug;155(4):1903-12 - PubMed
    1. Heredity (Edinb). 2002 Feb;88(2):94-101 - PubMed
    1. Chromosome Res. 1999;7(4):289-95 - PubMed
    1. Dev Genes Evol. 2000 May;210(5):243-9 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources