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.
