- Different species often are unable to interbreed among each other, and if they do, the offspring is usually sterile. This maintains diversity in life.
- In order to successfully fertilize an egg, a sperm has to outperform the other sperms competing to fertilize the same egg.
- This causes them to become increasingly motile and aggressive, sometimes to an extent that it may damage the uterus of the female that it is trying to fertilize.
- Female ovaries also become increasingly resistant to aggressive sperms. The consequent feature of which is neither optimal nor even harmful to the females.
- Within species, this “sexually antagonistic co-evolution” is usually in-sync so the sperm cells do not end up harming their own females.
- But, the sperm cell of one species has evolved to become more aggressive that can be handled by the females of another species, as a result of which the sperm may break through the female’s uterus, invade its ovaries and prematurely fertilize the egg leading to sterilization or even death of the female.
- Researchers at IIT Madras confirmed this theory while interbreeding Caenorhabditis worms by mating one of its hermaphrodite (self-mating) species to males of another species.
- The hermaphrodites, being used to a gentle sperm were prone to sterility and death. This has led scientists to believe that fertility problems could-be a by-product of sexual conflict among gametes in species with an evolutionary history of intense polygamous mating.
- This may help us understand better the evolution of sexual antagonism and also understand the formation of new species (termed as ‘mystery of mysteries’ by Charles Darwin).
- The team next plans of understanding how a single ancestral population that freely interbreed split into descendant populations that are averse to doing so.
- Read at:http://www.thehindu.com/todays-paper/tp-features/tp-sci-tech-and-agri/worm-sperm-sheds-light-on-darwins-mystery-of-mysteries/article6265802.ece