Studying turkeys could help researchers understand what makes some people more attractive than others, even if they have similar genetic traits.
A study determined it could be related to how the genes are used, a University College London press release reported.
"Sexual attractiveness varies markedly between individuals of the same sex. These differences can have a significant impact on how successful an individual is with the opposite sex," Professor Judith Mank, a UCL Research Department of Genetics, Evolution & Environment and senior author of the paper, said.
The researchers observed male-turkey brothers (with similar genetics), and found the more dominant individuals "show [a] higher expression of genes predominantly found in males, and a lower expression of genes predominantly found in females."
"Here, we have shown that male beauty is a result of how you use your genes, rather than the difference in the genes themselves," Mank said. "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."
Turkeys' level of dominance is determined the winter before they reach sexual maturity. Brothers participate in an epic battle for the most dominant rank, the losers become subordinates.
The most dominant male turkeys have certain ornate features, such as: "iridescent plumage, long beards and enlarged wattles," the Los Angeles Times reported. Subordinate males have less impressive traits.
Mank believes a similar outcome would be true in females. The most attractive woman would express their female genes significantly over their male-predominant ones.
What causes the change in genetics is still unknown. One possibility is extra testosterone "turns on" the male-predominant genes.
Alan Krakauer, an evolutionary biologist at UC Davis, who did not participate in the study, said the study was limited because it "assumed that dominant males are more masculine," the Los Angeles Times reported.
