Evolution and survival on eutherian sex chromosomes.
Evolution and survival on eutherian sex chromosomes.
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DOI：
10.1371/journal.pgen.1000568
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发表时间：
2009-07
期刊：
影响因子：
4.5
通讯作者：
Makova KD
中科院分区：
文献类型：
--
作者：
Wilson MA;Makova KD
Since the two eutherian sex chromosomes diverged from an ancestral autosomal pair, the X has remained relatively gene-rich, while the Y has lost most of its genes through the accumulation of deleterious mutations in nonrecombining regions. Presently, it is unclear what is distinctive about genes that remain on the Y chromosome, when the sex chromosomes acquired their unique evolutionary rates, and whether X-Y gene divergence paralleled that of paralogs located on autosomes. To tackle these questions, here we juxtaposed the evolution of X and Y homologous genes (gametologs) in eutherian mammals with their autosomal orthologs in marsupial and monotreme mammals. We discovered that genes on the X and Y acquired distinct evolutionary rates immediately following the suppression of recombination between the two sex chromosomes. The Y-linked genes evolved at higher rates, while the X-linked genes maintained the lower evolutionary rates of the ancestral autosomal genes. These distinct rates have been maintained throughout the evolution of X and Y. Specifically, in humans, most X gametologs and, curiously, also most Y gametologs evolved under stronger purifying selection than similarly aged autosomal paralogs. Finally, after evaluating the current experimental data from the literature, we concluded that unique mRNA/protein expression patterns and functions acquired by Y (versus X) gametologs likely contributed to their retention. Our results also suggest that either the boundary between sex chromosome strata 3 and 4 should be shifted or that stratum 3 should be divided into two strata. Using recently available marsupial and monotreme genomes, we investigated nascent sex chromosome evolution in mammals. We show that, in eutherian mammals, X and Y genes acquired distinct evolutionary rates and functional constraints immediately after recombination suppression; X-linked genes maintained lower, ancestral (autosomal), rates, whereas the evolutionary rates of Y-linked genes increased. Most X and, unexpectedly, Y genes evolved under stronger purifying selection than similarly aged autosomal paralogs. However, we also observed that the divergence of gametologs and paralogs shared similar features. In addition, many Y-linked copies evolved unique functions and expression patterns compared to their counterparts on the X chromosome. Therefore, our results suggest that to be retained on the Y chromosome, genes need to acquire separately valuable expression and/or functions to be safeguarded by purifying selection.
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DOI：
10.1098/rstb.2000.0717
发表时间：
2000-11-29
影响因子：
6.3
作者：
Charlesworth, B;Charlesworth, D
通讯作者：
Charlesworth, D
DOI：
10.1073/pnas.0801383105
发表时间：
2008-04-29
影响因子：
11.1
作者：
Bolliger, Marc F.;Pei, Jimin;Sudhof, Thomas C.
通讯作者：
Sudhof, Thomas C.
影响因子：
5.3
作者：
Lattanzi, W;Di Giacomo, M;Guanti, G
通讯作者：
Guanti, G
影响因子：
9.8
作者：
Bassi, MT;Ramesar, RS;Borsani, G
通讯作者：
Borsani, G
影响因子：
7
作者：
Hardison, RC;Roskin, KM;Haussler, D
通讯作者：
Haussler, D