As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Friday 18 March 2016

Pigeon foot feather genes identified

Study hints how scaly dinosaur legs could get birdlike feathers

Date: March 15, 2016
Source: University of Utah

Scientists identified two genes that make some pigeon breeds develop feathered feet known as muffs, while others have scaled feet. The same or similar genes might explain scaled feet in chickens and other birds, and provide insight into how some dinosaurs got feathers before they evolved into birds.

University of Utah scientists identified two genes that make some pigeon breeds develop feathered feet known as muffs, while others have scaled feet. The same or similar genes might explain scaled feet in chickens and other birds, and provide insight into how some dinosaurs got feathers before they evolved into birds.

The study found that in pigeons with feathers on their hindlimbs or feet, a hindlimb-development gene named Pitx1 is less active than normal, while a forelimb-development gene named Tbx5 is active in the feet, where it normally is not.

In other words, "pigeons' fancy feathered feet are partially wings," says biologist Mike Shapiro, senior author of the study published today by the journal eLife.

In mutant pigeons with foot feathers, "the hindlimb is clearly recognizable as a leg, but it has taken on more forelimb characteristics," he says. "It's not a complete transformation of a leg into a wing. Rather, components of the leg are more winglike, including feathers and a larger leg bone."

Shapiro and colleagues found that the Pitx1 and Tbx5 genes themselves are no different in breeds with and without foot muffs. Instead, they learned that nongene "regulatory sequences" of DNA near the genes act like switches to turn down the activity of hindlimb gene Pitx1 and turn up activity of forelimb gene Tbx5 in the embryos of pigeons with foot feathers.

"Our experiments show that these switches work differently in birds with feathered feet relative to the ones with normal, scaled feet," Shapiro says.
The two genes were previously known in all vertebrate animals, and they are linked to limb and other defects in people. The new study showed how they "provide a mechanism by which scaled and feathered skin regions can be controlled," Shapiro says.




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