Natural Selection Reduced Diversity on Human Y Chromosomes
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Natural Selection Reduced Diversity on Human Y Chromosomes. / Wilson Sayres, Melissa A.; Lohmueller, Kirk E.; Nielsen, Rasmus.
In: PLOS Genetics, Vol. 10, No. 1, e1004064, 2014.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Natural Selection Reduced Diversity on Human Y Chromosomes
AU - Wilson Sayres, Melissa A.
AU - Lohmueller, Kirk E.
AU - Nielsen, Rasmus
PY - 2014
Y1 - 2014
N2 - The human Y chromosome exhibits surprisingly low levels of genetic diversity. This could result from neutral processes if the effective population size of males is reduced relative to females due to a higher variance in the number of offspring from males than from females. Alternatively, selection acting on new mutations, and affecting linked neutral sites, could reduce variability on the Y chromosome. Here, using genome-wide analyses of X, Y, autosomal and mitochondrial DNA, in combination with extensive population genetic simulations, we show that low observed Y chromosome variability is not consistent with a purely neutral model. Instead, we show that models of purifying selection are consistent with observed Y diversity. Further, the number of sites estimated to be under purifying selection greatly exceeds the number of Y-linked coding sites, suggesting the importance of the highly repetitive ampliconic regions. While we show that purifying selection removing deleterious mutations can explain the low diversity on the Y chromosome, we cannot exclude the possibility that positive selection acting on beneficial mutations could have also reduced diversity in linked neutral regions, and may have contributed to lowering human Y chromosome diversity. Because the functional significance of the ampliconic regions is poorly understood, our findings should motivate future research in this area.
AB - The human Y chromosome exhibits surprisingly low levels of genetic diversity. This could result from neutral processes if the effective population size of males is reduced relative to females due to a higher variance in the number of offspring from males than from females. Alternatively, selection acting on new mutations, and affecting linked neutral sites, could reduce variability on the Y chromosome. Here, using genome-wide analyses of X, Y, autosomal and mitochondrial DNA, in combination with extensive population genetic simulations, we show that low observed Y chromosome variability is not consistent with a purely neutral model. Instead, we show that models of purifying selection are consistent with observed Y diversity. Further, the number of sites estimated to be under purifying selection greatly exceeds the number of Y-linked coding sites, suggesting the importance of the highly repetitive ampliconic regions. While we show that purifying selection removing deleterious mutations can explain the low diversity on the Y chromosome, we cannot exclude the possibility that positive selection acting on beneficial mutations could have also reduced diversity in linked neutral regions, and may have contributed to lowering human Y chromosome diversity. Because the functional significance of the ampliconic regions is poorly understood, our findings should motivate future research in this area.
U2 - 10.1371/journal.pgen.1004064
DO - 10.1371/journal.pgen.1004064
M3 - Journal article
C2 - 24415951
AN - SCOPUS:84893816707
VL - 10
JO - P L o S Genetics
JF - P L o S Genetics
SN - 1553-7390
IS - 1
M1 - e1004064
ER -
ID: 222644097