Chicken Beards Linked to Gene
A chromosomal rearrangement, and not a good barber, explains why some chickens grow beards.
The findings, published in the journal PLOS Genetics could, in future, shed light on the evolution and development of feathers in all birds.
The facial feather phenomenon is called "muffs and beard," or Mb for short.
Lead author Ying Guo of China Agricultural University and his team explained, "Muffs and beard is a phenotype (observable characteristic) in chickens where groups of elongated feathers gather from both sides of the face (muffs) and below the beak (beard)."
WATCH: Can We Genetically Engineer a Dino from a Chicken?
The extra feathers don't appear to serve any particular function, but to people they can certainly look snazzy and often appeal to bird breeders.
The scientists analyzed DNA from the chickens and identified the location on a chromosome that is associated with the unique traits. Guo and his team next sequenced that region from chickens both with and without beards.
The researchers found that chickens with beards have three duplicated regions of a chromosome called 27. One of the duplicates, HOXB8, is a gene known to function in feather development. It was present at high levels in the facial skin of chickens with beards, but not in the other chickens included in the study.
Prior research has linked this same gene in other animals to everything from compulsive grooming in mice to colon cancer in humans. While this latest study just focused on one novel trait in chickens, the findings reveal more about genetic variation, which is key to the evolution and development of every animal. As the researchers wrote, "The chicken is an attractive avian species for genetics research ..."
In this case, the bearded chickens were attractive in all respects.
SEE PHOTOS: Flightless Birds: It Takes One Step at a Time
One of the things we learned about this week was a
for the species of this not-so-little fella. It's a kakapo, the world's heaviest parrot as well as the only flightless parrot. The kakapo's also critically endangered, its long history without the defensive measure of flight bringing it to the brink of extinction. "Flightless bird," of course, sounds like a contradiction, but there are actually dozens of birds out there that can't fly. They don't have it easy, without a flight plan to help them out of trouble, and some of them are hanging by a thread. But, they're still here! In honor of the kakapo's welcome population explosion, let's look at a sampling of other birds that make a living on the ground and never glimpse the world from high in the sky.
Here's perhaps the most famous flightless bird, the dodo. It's also known --
, it turns out -- as a bit of an avian dumbbell. (They were actually
with pigeons in intelligence.) They went extinct by 1622, on their island home of Mauritius. They were done in by hunters as soon as mankind arrived to live among the guileless birds.
What else is there to say about penguins? They're cute, classy, good swimmers, but, alas, non-fliers.
Emu's eschew flight, too. As you can see from this emu that had run amok in Texas, they're tall drinks of water -- the second-tallest bird after the ostrich (about which more later). Emus can exceed 6 feet tall, and they can run up to 30 miles per hour.
The cassowary lives in tropical New Guinea and northeastern Australia. It's also tall -- the southern cassoway species being third-tallest among birds, after the ostrich and the emu. They like to keep to themselves and prefer you would too. They can harm people if their feathers are ruffled, metaphorically or literally.
Meet the tallest bird in the world, the ostrich. How tall? Males can run anywhere from 6 feet up to 9 feet tall. They're native to Africa and, like the emu, have some impressive land speed potential: they can run up to 43 miles per hour. Unfortunately for ostriches, they're heavily farmed for their feathers and for their skin. The former for decoration and for dusters; the latter for leather products. Its meat is also sold in commercial markets.
The inaccessible island rail (yes, that's really it's name) is the lone species in its genus, living on Inaccessible Island (yes, that's really it's name) in the Tristan Archipelago in the southern Atlantic. It's just under 7 inches long and weighs about 1 ounce, and those humble stats make it the smallest of the world's flightless birds. It's luckier than some other flightless birds in that its island home is free of introduced predators, so it has been able to make a decent living there.
Kiwis are native New Zealanders, roughly the size of chickens. They maintain a largely nocturnal lifestyle and when pairs of their kind mate, kiwi males and females stay together for life. The kiwi is the national symbol of New Zealand.
Domestic chickens can't fly for anything but the tiniest hops, having lost the ability to jet for any distance.
Domestic ducks, like chickens and unlike mallards, aren't much for flying either.