Pigeon Genome Decoded: Gene Mutation Linked To Fancy Hairdo

Researchers have identified a gene that is responsible for the fancy head crests of rock pigeons.

AsianScientist (Feb. 4, 2013) – Researchers have sequenced the genome of the rock pigeon (Columba livia), revealing the genetic cause of a specific trait that gives some pigeons what looks like a fancy feather hairdo. The discovery paves the way for the identification of other genes responsible for other traits in pigeons.

In their study, which was published online in Science, the researchers sequenced and assembled a high quality genome map of a male pigeon of the Danish tumbler breed.

They then went on to carry out more limited sequencing on the genomes of two feral pigeons (which are free-living but not wild) and another 38 pigeons from 36 different breeds.

Through their analysis, the researchers pinpointed a single mutation in a gene named EPHB2 to be the cause of a pigeon trait known as a head crest.

There are some 350 breeds of pigeon and 80 of them have head crests. Head crests play a role in attracting mates in many bird species and come in shapes known as hoods, manes, shells and peaks.

“A head crest is a series of feathers on the back of the head and neck that point up instead of down,” says Dr. Michael Shapiro, one of the study’s senior authors. “Some are small and pointed. Others look like a shell behind the head.”

The researchers found strong evidence that the EPHB2 gene acts like an on-off switch to create a head crest when mutant, and no head crest when normal.

By studying a larger pool of 69 crested pigeons from 22 breeds, and 95 pigeons from 57 breeds, the researchers confirmed that all crested pigeons had the mutant version of the gene while the uncrested birds did not.

Their analysis further ruled out the possibility that the mutation arose independently in different breeds, showing that the trait evolved just once and was likely spread to numerous breeds by breeders.

The researchers also identified the mechanism by which the genetic mutation causes head crests to develop: the mutant gene affects pigeon embryos by reversing the direction of feather buds (from which fathers later grow).

To track the trait, the team adapted and used a gene-finding software that was originally developed to find mutations that control human diseases.

The researchers are hopeful that their approach can be extended to identifying mutations that control other interesting traits in pigeons, and also in other animals.

The article can be found at: Shapiro et al. (2013) Genomic Diversity And Evolution Of The Head Crest In The Rock Pigeon.

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Source: BGI. Photo: Michael D. Shapiro/University of Utah.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Yew Chung is a postdoctoral research fellow at the Duke-NUS Graduate Medical School, Singapore.

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