However, this does not happen, which gives us the Lek Paradox and the enormous variation between individuals.

This paradox has been a persistent problem to evolutionary biologists because the great genetic diversity within humans seems not to be something that should happen.

However, Marion Petrie, professor of behavioral ecology (evolutionary biology group) at Newcastle University (Newcastle upon Tyne, England), and her team of English scientists believe that have found a solution to the Lek Paradox. (Lek stands for the activity of a group of males, in some animal species, to gather together for the competitive purpose of mating—primarily to show off their physical attributes).

Beneficial mutations are believed to be in work within humans. Instead of a detrimental mutation, such as the spreading of cancerous cells, some mutations actually help individuals with such things as being more resistant to viruses and bacteria. When this happens, more mutations result. And, consequently, a higher mutation rate creates more diversity in a population.

Thus, men with greater genetic diversity are rated as more attractive by women. These men are more likely to have sex with women and, consequently, to pass their high diversity rate on to the next generation, which is why we have a great variation in looks in our population.

Petrie states: "We find that sexual selection can promote genetic diversity despite expectations to the contrary."

The research was published March 28, 2007 in the academic journal Heredity, part of the Nature Publishing Group.

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