For Turkeys, Sex Appeal Less About Genes One's Born with than Their Expression

It's not so much the genes they come with but how they use them that defines the sexual attractiveness of male turkeys, a new study shows.

Published in the journal PLoS Genetics, the study represents an effort on behalf of geneticists from the University of College London and the University of Oxford to answer the question as to why genetically similar individuals are considered different in terms of their sexual allure.

In examining turkeys, the scientists found that among brothers, "dominant" males showed a higher expression of genes predominantly found in males and a lower expression of those largely found in females when compared to their less successful brothers.

In other words, the researchers explain, the male's attractiveness is a result of the expression of their genes rather than the genes in and of themselves.

"Sexual attractiveness varies markedly between individuals of the same sex," Judith Mank of the UCL Research Department of Genetics, Evolution and Environment and senior author of the paper said. "These differences can have a significant impact on how successful an individual is with the opposite sex."

And while humans may not have clearly defined roles of either dominant or subordinate men and women, Mank explains that we "do exhibit a range of sexual dimorphisms -- some individuals are more attractive to the opposite sex than others."

For turkeys, this pecking order is defined the winter before they reach sexual maturity during a fierce battle pitting brother against brother. Only the winning turkey will go on to sire offspring while the others become something of an assistant in helping him woo the females. As to why some male turkeys become dominant or submissive researchers aren't sure, though most suspect it has something to do with the concentration of male hormones affecting gene expression.

Going forward, Mank says she and her colleagues suspect to find similar results in terms of female turkeys, with the more sought out exhibiting "a higher expression of genes predominantly found in females and lower expression of male genes."