Men with multiple mates (loose zippers) add to human diversity

William Atkins
Wednesday, 05 November 2008 21:32

Science - Biology

These tests were DNA-based analysis of forty independent loci on the X chromosome and autosomes (non-sex chromosomes).

The U.S. researchers stated, “To correct for mutation rate heterogeneity among loci, we divide our diversity estimates within human populations by divergence with orangutan at each locus.”

They found that the X chromosome was more diverse genetically than would normally be expected if males and females had passed on their genes equally from generation to generation.

Thus, they conclude, “Consistent with expectations under a model of polygyny, we find elevated levels of X-linked versus autosomal diversity.”

They contend that, “While it is possible that multiple demographic processes may contribute to the observed patterns of genomic diversity (i.e., background selection, changes in population size, and sex-specific migration), we conclude that an historical excess of breeding females over the number of breeding males can by itself explain most of the observed increase in effective population size of the X chromosome.”

In other words, men got many more women pregnant over the ages, thus producing a wide difference in how humans developed genetically.

From the 1869 book Little Women by Louisa May Alcott, it is quoted: “Boys will be boys, young men must sow their wild oats, and women must not expect miracles”.

And, the Rolling Stones said it equally well in the title of their 1970 album: “Get Your Ya-Ya's Out!”

Overall, the results of this study help scientists to understand better the diversity of the human genome (the full set of chromosomes or genes found in humans as based on the hereditary information found in DNA).