Sexual practice of polygyny skews genetic variability

Sep 26, 2008

Researchers have found DNA evidence that polygyny, the practice among males of siring children with multiple female partners at the same time or successively, has led to an excess of genetic diversity on the X chromosome relative to the autosomes. Details are published Sep. 26 in the open-access journal PLoS Genetics.

Women have been more successful on average in passing their genes on to the next
generation. "This is because a few males have fathered children with multiple females, which occurs at the expense of other less successful males", says Dr. Michael Hammer, ARL Division of Biotechnology at the University of Arizona.

The group has found DNA evidence that polygyny, the practice among males of siring
children with multiple female partners at the same time or successively, has led to an excess of genetic diversity on the X chromosome relative to the autosomes. Details are published September 26 in the open-access journal PLoS Genetics.

The X chromosome is present in two copies in females and a single copy in males. The autosomes, which are inherited equally by both sexes from each parent, are expected to have more genetic diversity than the X chromosome in a population with an equal number of breeding males and females.

The article examines potential demographic and evolutionary forces that have led to higher than expected genetic variation on the X chromosome. The research team measured levels of neutral polymorphism at 40 independent loci on the X chromosome and autosomes in ninety humans representing six populations, including: Biaka (Central African Republic), Mandenka (Senegal), San (Namibia), French Basque, Han Chinese and Melanesians (Papua New Guinea). The group contrasted alternative explanations for the higher observed levels of X-linked (versus autosomal) diversity.

Background selection, changes in population size and sex-specific migration were
all discounted as contributors to the observed patterns of genetic variability. Only the process of polygyny could by itself account for the sex ratio skew and resulting patterns of genomic variation. By this process, fewer unique male genes are being passed into the next generation.

The group's research highlights how unseen, sex-biased forces have shaped genomic patterns of variability. Over the long-term, the findings may provide lessons on the dynamics of beneficial mutations on different chromosomes as they sweep through the population.

Citation: Hammer MF, Mendez FL, Cox MP, Woerner AE, Wall JD (2008) Sex-Biased Evolutionary Forces Shape Genomic Patterns of Human Diversity. PLoS Genet 4(9): e1000202. doi:10.1371/journal.pgen.1000202 dx.plos.org/10.1371/journal.pgen.1000202

Source: Public Library of Science

Explore further: A different kind of green movement: Seedling growth in space

add to favorites email to friend print save as pdf

Related Stories

Still no 'justice for all' for female athletes

Aug 04, 2014

Spanish hurdler María José Martínez-Patiño, who in the 1980s endured harsh global media attention when she was subjected to unscientific gender tests, is co-author of a study that takes stock of current sexual verification ...

Molecular monkey arranges X-chromosome activation

Jul 25, 2013

X chromosomes are very special genetic material. They differ in number between men and women. To achieve equality between sexes, one out of two X chromosomes in women is silenced. In flies, the opposite happens: ...

The pig whipworm genome may aid to treat autoimmune diseases

Jun 20, 2014

An international team, composed of 11 institutions from six countries, including BGI, presented the whole-genome sequence of Trichuris suis, a parasitic worm in pig. Understanding the genetics mechanisms underlying the pi ...

Recommended for you

Reading a biological clock in the dark

1 hour ago

Our species' waking and sleeping cycles – shaped in millions of years of evolution – have been turned upside down within a single century with the advent of electric lighting and airplanes. As a result, ...

User comments : 0