Exchange of genetic information between therian X and Y chromosome gametologs in old evolutionary strata. Issue 20 (12th September 2017)

• Record Type: Journal Article
• Authors: Peneder, Peter; Wallner, Barbara; Vogl, Claus
• Is Part Of: Ecology and evolution. Volume 7:Issue 20(2017:Nov.)
• Page Start: 8478
• Page End: 8487
• Publication Date: 2017-09-12
• Subjects: comparative method -- evolutionary strata -- gene conversion -- sex chromosome evolution -- therians; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.3278
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Therian X and Y sex chromosomes arose from a pair of autosomes. Y chromosomes consist of a pseudoautosomal region that crosses over with the X chromosome and a male‐specific Y ‐chromosomal region that does not. The X chromosome can be structured into "evolutionary strata". Divergence of X‐chromosomal genes from their gametologs is similar within a stratum, but differs among strata, likely caused by a different onset of suppression of crossing over between gametologs. After stratum formation, exchange of information between gametologs has long been believed absent; however, recent studies have shown limited exchange, likely through gene conversion. Herein we investigate exchange of genetic information between gametologs in old strata that formed before the split of Laurasiatheria (cattle) from Euarchontoglires (primates and rodents) with a new phylogenetic approach. A prerequisite for our test is an overall preradiative topology, that is, all X‐chromosomal gametologs are more similar among themselves than to Y‐chromosomal sequences. Screening multiple sequence alignments of the coding sequences of genes from cattle, mice, and humans identified four genes, DDX3X/Y, RBMX/Y, USP9X/Y, and UTX/Y, exhibiting a preradiation topology. Applying our test, we detected exchange of genetic information between all four X and Y gametologs after stratum formation. Abstract : Preradiation phylogeny of X and Y gametologs in the three species Bos, Homo, and Mus . Time is measured in millions of years before present. The X gametolog is characterized by thick lines and the Y gametolog by thin lines. The broken lines at the base indicate a variable time of differentiation of gametologs before the split of the Laurasiatheria from the Euarchontoglires. bx, hx, and mx are the terminal branches of the X gametolog phylogeny leading to cattle, humans, and mice, respectively, and sx is the internal branch uniting the Euarchontoglires humans and mice after the split of Laurasiatheria. by, hy, my, and sy are the respective branches on the Y gametolog. Gametologs within the same organism may exchange genetic information.