Posted: February 24, 2012, 4:15 p.m. PST
Courtesy Michael Shapiro
crests in two breeds of domestic pigeon that are not genetically very similar.
Researchers from the University of Utah say they have traced the pigeon’s family tree in an effort to sort out the abundant variations in the pigeon species.
The results were published online under the study title, “Divergence, Convergence and the Ancestry of Feral Populations in the Domestic Rock Pigeon,” on January 19, 2012 in Current Biology, a Cell Press publication.
Pigeons are more diverse than any other bird species, according to the researchers. Pigeons come in all colors, shapes and sizes. Some have feathers reaching up over their heads like a hood. Others have feathers all the way to the tips of their toes or fanned out on their tails like a turkey’s. Pigeon beak size also varies.
“Most people think of pigeons as rats of the sky, but domestic pigeon breeds are wonderfully diverse,” said Michael Shapiro, one of the researchers. “There are over 350 breeds that differ in color and color pattern, body size, beak size and shape, skeletal structure, posture, feather placement and behavior. Our goal is to track down the DNA-level changes that control some of these interesting differences among breeds.”
The researchers used a large, geographically diverse sample of 361 individuals from 70 domestic pigeon breeds and two free-living populations to determine genetic relationships within the species.
They found that in many cases, species with similarly bold traits are closely related. However, in other cases, that wasn’t the case. This means that some of the pigeons’ distinct characteristics may have arisen more than once on different branches of the birds’ family tree or spread from one branch to another through interbreeding, according the study.
Shapiro’s team also found that two feral pigeon populations — one in Salt Lake City and another in Scotland — have mixed with racing breeds, such that they are now genetically very similar to those used in competitions around the world.
Modern breeds are frequently described as originating in England, Germany, Belgium or other areas of Europe, but their progenitors were probably brought there from afar by traders or colonialists, according to the researchers. For instance, the researchers were able to trace the geographic origin of some breed groups to India and the Middle East.
Overall, the researchers say that the genetic history of pigeons is a critical framework for the analysis of the genetic control of many novel traits in this species.
The researchers also say that studies of pigeons may also help to explain variation among wild birds and perhaps other animals as well.
“The striking differences we see between breeds within this single species are characteristic of the types of differences we typically see between species,” Shapiro said. “Our hope is that by understanding the genes that control pigeon diversity, we’ll have a great starting point to understand diversity in the wild.”