What Causes Attraction?

There is a lot of societal pressure today to look attractive. However, beauty has always been a subjective concept. It is understood that certain people find specific traits more alluring than others. And so, it became the misconception that specific genes that code for these traits are the cause of sexual attraction. Scientists’ explored sexual dimorphism and sex linked traits in order to see their effects on sexual selection. However, something never made sense. Why would brothers that are genetically similar differ in their ability to find a mate?

A newly published article in PLoS Genetics reveals the answer in its study of wild turkeys. It turns out that attractiveness is not the result of what genes are present in an individual but how they are used. Scientists found that in brothers (of wild turkey), attractiveness was due to gene expression. The dominant brother would express more masculine genes than that of the submissive brother. Whether a brother was dominant or submissive would be decided after a fight for dominance the winter before they reach sexual maturity. The dominant brother would have a higher fitness level. It is speculated that hormones play a role on whether an individual would become dominant or not.

But what does this have to do with human beings? Professor Judith Mank, UCL Department of Genetics, states that “even though humans don’t have clear dominant and subordinate types, they do exhibit a range of sexual dimorphisms – some individuals are more attractive to the opposite sex than others.” Scientists hope that understanding the roles of genetic makeup in other organisms will one day give us a better understanding of sexual dimorphism in sexual selection for human beings.  The study of wild turkeys is the first step towards that goal.