Genetic Mutations Determine Color of Pigeon Plumage

Mutations in three key genes determine feather color in domestic rock pigeons, scientists report. These same genes control pigmentation of human skin.

"Mutations in these genes can be responsible for skin diseases and conditions such as melanoma and albinism," said Michael Shapiro, associate professor of biology and senior author of the study published in Current Biology.

"In humans, mutations of these genes often are considered 'bad' because they can cause albinism or make cells more susceptible to UV (ultraviolet sunlight) damage and melanoma because the protective pigment is absent or low," said Eric Domyan, a biology postdoctoral fellow and first author of the study. "In pigeons, mutations of these same genes cause different feather colors, and to pigeon hobbyists that is a very good thing."

Drawing on their centuries-long experience, pigeon breeders have produced about 350 distinct pigeon breeds, focusing particularly on beak shape, plumage color and feather ornamentation. Before Domyan's study, the specific mutations that control color in rock pigeons were unknown.

"Across all pigeon breeds, mutations in three major genes explain a huge amount of color variation," Shapiro said.

"Various forms of a gene named Tyrp1 make pigeons either blue-black (the grayish color of common city pigeons), red or brown. Mutations of a second gene, named Sox10, makes pigeons red no matter what the first gene does. And different forms of a third gene, named Slc45a2, make the pigeons' colors either intense or washed out," according to a press release announcing the findings.

Pigeon color is dictated by different versions of these three genes and certain "epistatic" interactions, in which one gene obscures the expression of another gene, according to the scientists.

"Our work provides new insights about how mutations in these genes affect their functions and how the genes work together," Shapiro said. "Many traits in animals, including susceptibility to diseases such as cancer, are controlled by more than one gene. To understand how these genes work together to produce a trait, we often have to move beyond studies of humans. It's difficult to study interactions among the genes in people."