Natural Selection Reduced Diversity on Human Y Chromosomes

Melissa Wilson Sayres, Kirk E. Lohmueller, Rasmus Nielsen

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Article numbere1004064
JournalPLoS Genetics
Volume10
Issue number1
DOIs
StatePublished - Jan 2014
Externally publishedYes

Fingerprint

Chromosomes, Human, Y
Genetic Selection
Y Chromosome
Y chromosome
natural selection
chromosome
Mutation
mutation
Nucleic Acid Repetitive Sequences
Population Genetics
Population Density
Mitochondrial DNA
Genome
effective population size
mitochondrial DNA
population genetics
population size
genome
genetic variation
simulation

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Ecology, Evolution, Behavior and Systematics
  • Cancer Research
  • Genetics(clinical)

Cite this

Natural Selection Reduced Diversity on Human Y Chromosomes. / Wilson Sayres, Melissa; Lohmueller, Kirk E.; Nielsen, Rasmus.

In: PLoS Genetics, Vol. 10, No. 1, e1004064, 01.2014.

Research output: Contribution to journalArticle

Wilson Sayres, Melissa ; Lohmueller, Kirk E. ; Nielsen, Rasmus. / Natural Selection Reduced Diversity on Human Y Chromosomes. In: PLoS Genetics. 2014 ; Vol. 10, No. 1.
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