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Scientists at the University of Lausanne have found how natural selection changed owls’ appearance over 10 generations in a large-scale genetic study of feather color and spotting.
Operative Information Center-OMM reports that the study, published in the journal “Nature Communications,” was led by Dr. Tristan Cumer and Professor Jerom Gude.
Researchers identified DNA variants linked to color and spotting using field observations collected over decades and whole-genome sequencing of more than 3,000 owls. According to the scientists, the increase in genetic variants associated with reddish-brown feathers is explained not by random processes but by the direct influence of natural selection.
The study identified the MC1R gene, which affects pigmentation, as well as specific regions on the sex chromosome. However, MC1R also belongs to the melanocortin system, which regulates physiological traits including responses to stress and aggressiveness, in addition to color. The scientists therefore say natural selection may act directly on the birds’ ability to withstand stress rather than on feather color, with the color change emerging as a side effect.
Barn owls’ plumage ranges from completely white to dark reddish-brown. White owls use moonlight when hunting, while birds with many dark spots are more resilient to parasites and food shortages. Professor Alexandre Roulin, one of the study’s co-authors, said environmental changes and prey availability — for example, an increase in field mice — may have given reddish-brown owls an advantage.
