Darolti, I;
Wright, AE;
Mank, JE;
(2020)
Guppy Y chromosome integrity maintained by incomplete recombination suppression.
Genome Biology and Evolution
10.1093/gbe/evaa099.
(In press).
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Abstract
The loss of recombination triggers divergence between the sex chromosomes and promotes degeneration of the sex-limited chromosome. Several livebearers within the genus Poecilia share a male-heterogametic sex chromosome system that is roughly 20 million years old, with extreme variation in the degree of Y chromosome divergence. In P. picta, the Y is highly degenerate and associated with complete X chromosome dosage compensation. In contrast, although recombination is restricted across almost the entire length of the sex chromosomes in P. reticulata and P wingei, divergence between the X and the Y chromosome is very low. This clade therefore offers a unique opportunity to study the forces that accelerate or hinder sex chromosome divergence. We used RNA-seq data from multiple families of both P. reticulata and P. wingei, the species with low levels of sex chromosome divergence, to differentiate X and Y coding sequence based on sex-limited SNP inheritance. Phylogenetic tree analyses reveal that occasional recombination has persisted between the sex chromosomes for much of their length, as X- and Y-linked sequences cluster by species instead of by gametolog. This incomplete recombination suppression maintains the extensive homomorphy observed in these systems. In addition, we see differences between the previously identified strata in the phylogenetic clustering of X-Y orthologs, with those that cluster by chromosome located in the older stratum, the region previously associated with the sex-determining locus. However, recombination arrest appears to have expanded throughout the sex chromosomes more gradually instead of through a stepwise process associated with inversions.
| Type: | Article |
|---|---|
| Title: | Guppy Y chromosome integrity maintained by incomplete recombination suppression |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/gbe/evaa099 |
| Publisher version: | https://doi.org/10.1093/gbe/evaa099 |
| Language: | English |
| Additional information: | Copyright © The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | gametologs, non-recombining region, poecilid, sex-linked genes |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Genetics, Evolution and Environment |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10099114 |
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