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GENES behind the immune system may
explain why some women have more sexual partners than others.
The major histocompatibility complex
(MHC) is a region of DNA vital to the immune system. The more diverse
the genes of the MHC, the more effective it is at conferring disease
resistance, and in a variety of animals individuals with diverse MHCs
are more likely to be chosen as a sexual partner. Its effect in humans,
however, is unclear.
Hanne Lie of the University of Western
Australia in Perth measured the diversity of the MHC in 74 heterosexual
female students and asked them about the number of sexual partners they
had had. After controlling for attitudes towards sex and age of first
intercourse, she found that the greater a woman's MHC diversity, the
more sexual partners she had had. There was no correlation with overall
genetic diversity (Animal Behaviour, DOI: 10.1016/j.anbehav.2009.12.040).
Whether this means women with diverse
MHCs have greater evolutionary success is debatable. Boguslaw Pawlowski,
an anthropologist at the University of Wroclaw, Poland, points out that
contraception means there may not be a strong correlation between
number of sexual partners and reproductive success.
Source: http://www.newscientist.com/article/mg20527504.800-women-with-good-genes-may-have-more-sexual-partners.html (2010)
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