Journal
MOLECULAR BIOLOGY AND EVOLUTION
Volume 29, Issue 12, Pages 3741-3754Publisher
OXFORD UNIV PRESS
DOI: 10.1093/molbev/mss177
Keywords
neo-sex chromosome; ZW gametolog divergence; recombination cessation
Funding
- Swedish Research Council
- Crafoord Foundation
- Wenner-Gren Foundation
- Helge Axson Johnsons Stiftelse
Ask authors/readers for more resources
Newer parts of sex chromosomes, neo-sex chromosomes, offer unique possibilities for studying gene degeneration and sequence evolution in response to loss of recombination and population size decrease. We have recently described a neo-sex chromosome system in Sylvioidea passerines that has resulted from a fusion between the first half (10 Mb) of chromosome 4a and the ancestral sex chromosomes. In this study, we report the results of molecular analyses of neo-Z and neo-W gametologs and intronic parts of neo-Z and autosomal genes on the second half of chromosome 4a in three species within different Sylvioidea lineages (Acrocephalidea, Timaliidae, and Alaudidae). In line with hypotheses of neo-sex chromosome evolution, we observe 1) lower genetic diversity of neo-Z genes compared with autosomal genes, 2) moderate synonymous and weak nonsynonymous sequence divergence between neo-Z and neo-W gametologs, and 3) lower GC content on neo-W than neo-Z gametologs. Phylogenetic reconstruction of eight neo-Z and neo-W gametologs suggests that recombination continued after the split of Alaudidae from the rest of the Sylvioidea lineages (i.e., after similar to 42.2 Ma) and with some exceptions also after the split of Acrocephalidea and Timaliidae (i.e., after similar to 39.4 Ma). The Sylvioidea neo-sex chromosome shares classical evolutionary features with the ancestral sex chromosomes but, as expected from its more recent origin, shows weaker divergence between gametologs.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available