New evidence for female control in re...( WASHINGTON D.C. Adding another laye...)

WASHINGTON, D.C. Adding another layer of competition to the mating game, scientists are reporting possible biochemical proof that the reproductive system of female mammals can sense the presence of sperm and react to it by changing the uterine environment. This may be the molecular mechanism behind post-copulatory sexual selection, in which females that have mated with several partners play a role in determining which sperm fertilizes their egg.

Lead author Alireza Fazeli says that the deep new molecular insights into this post-coital ladies choice has profound implications for in-vitro fertilization (IVF), cloning, and animal breeding. It is also a windfall for evolutionary biology, providing a possible explanation for female promiscuity in the animal kingdom, he adds.

In a first-of-its-kind study scheduled for ACS Journal of Proteome Research, Fazelis international scientific team reports the first chemical evidence of a sperm recognition system in the oviducts of pigs standard animals for such research because their reproductive systems are similar to humans.

In the traditional view, competition for the egg is male-oriented, with sperm themselves deciding which fertilizes the egg by being the faster swimmer. With post-copulatory sexual selection, the female is in control, her oviducts selecting the winner the best quality sperm from the healthiest male and rejecting the rest.

This study clearly shows that the sperms arrival in the female reproductive tract triggers a cascade of changes that leads to alteration of protein production in the oviduct and a change in the oviductal environment. We speculate that this is mainly done to prepare oviduct environment for storing sperm, fertilization and early embryonic development, Fazeli said. However this can also be used as a detection and selection system that alerts females to the presence of different kinds of sperm and then triggers mechanisms in the oviducts that control
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