As genetic researchers continue to better understand the mode of operation in gene combinations, it becomes increasingly obvious that only slight genetic variations can bear significantly different results in the natural world. The most recent finding in this regard comes from a team of researchers at the University of Texas at Arlington, who in studying pigeons as part of further exploring vertebrate evolution, managed to discover that mutations and interactions that take place between just three genes spin out a broad variety of color variations in the birds. As a result, the researchers have discovered that one of these genes is a kind of “slippery gene” that may give rise to significant evolutionary changes.
UT Arlington biology professor Dr. John W. “Trey” Fondon is co-author of this new study, which has begun to shed light on the color palette of domestic pigeons at the molecular level. These domestic pigeons, also known as “fancy pigeons,” present in many color variations, mostly due to highly organized breeding in Europe and Asia. The result has been spin-offs of the traditional blue/black color model, including shades of gray, red, and brown.
The genes that have been discovered in determining all of these variations are not abstract; they directly impact our understanding of human genetics, as the genes in pigeons have previously been linked to skin and hair color variation among people — important considerations in the study of understanding and treating some malignancies in humans, such as melanoma.
Dr. Fondon explained that,”The pigeon really has been neglected as a model system, and we are changing that,” and adding that this new pigeon study can help in an overall understanding of vertebrate systems, which in turn will impact human health. “The things that shape diversity also shape disease.”
The results of the study, which were published online on February 6th in the journal Current Biology, features Eric T. Domyan, a post-doctoral fellow in the lab of University of Utah professor Michael D. Shapiro, as the study’s lead author. Shapiro’s team at University of Utah began the project last year, when they published in the journal Science results from the first large-scale sequencing of the pigeon genome, which yielded valuable genetic data from 40 pigeons.
The research team determined that three genes — Tyrp1, Sox10 and Slc45a2 — control multiple color phenotypes, or appearances, in pigeons, according to a recent press release. For example, “researchers found that the ash-red mutation in Tyrp1, a gene that plays a large role in color determination, arose just once and was spread throughout the species by selective breeding.”
This is also where the “slippery gene” was discovered, which may hold a key to understanding vertebrate evolution.
“Fondon’s team found two independent deletions of regulatory sequences near the Sox10 gene produce “recessive red” pigmentation. These mutations happened at different points in evolution, and researchers believe it is no coincidence they hit the same spot, as this same region is also deleted in color mutants of chickens and mice, Fondon said. There are indications of yet more independent mutations of this ‘hotspot.'”
This is not the first time that geneticists like Fondon have used animal species to study vertebrate evolution and create a knowledge bridge that ultimately benefits human health. Dr. Fondon in the past has studied dog breeds to better understand phenotype changes at the molecular level, given the diverse variations in dog breeds. Fondon now believes that domestic pigeons can yield even greater statistical power for researchers.
“These traits are falling like dominoes in terms of our understanding their genetic origins. It took hundreds of years to set them up and now they are just falling,” Fondon said.
Other co-authors include Shapiro; Shreyas Krishnan and Clifford Rodgers, of UT Arlington; Zev Kronenberg, Michael W. Guernsey, Anna Vickery and Mark Yandell, of University of Utah; Raymond E. Boissy, of the University of Cincinnati College of Medicine; and Pamela Cassidy and Sancy A. Leachman, of the Oregon Health & Science University.