Scientists Find the Key to a City Bird’s Hue

A pigeon’s style is determined by three genes.

Pigeons are the epitome of the urban landscape, one of only a few species that thrive in a concrete jungle. They tend to come in hues that blend with the gray surroundings, but some are shockingly colorful—crimson, hazel, even gold.

A new study decodes the genes that can determine what makes a pigeon common gray or rare primrose. The research, published in Current Biology,reveals that it comes down to mutations in three specific genes linked to plumage, which are parallel to the genes associated with skin pigmentation in humans.

Using DNA extracted from blood and feather samples collected at pigeon shows in Utah, the scientists found specific variations in the trio of genes. A mutation in the first gene, called Tyrp1, which gives a bird a blue-black hue, paints a pigeon ash red or cinnamon brown. A mutation in a second gene called Sox10, which is recessive, results in red, regardless of the effect of Tyrp1. Differences in the third gene determine whether the shade of a pigeon’s color will be intense or dull.

“In humans, mutations of these genes often are considered ‘bad’ because they can cause albinism or make cells susceptible to UV (ultraviolent sunlight) damage and melanoma because the protective pigment is absent or low,” said Eric Domyan, a biology postdoctoral fellow from the University of Utah, who authored the paper. He explained that in pigeons the genetic differences are innocuous. A mash-up of mutations in these three genes results in 82 different pigeon breeds.

The new finding proves that a plain city bird is not so plain after all.