Posts tagged "genetics"

From chihuahuas to bulldogs to giant Great Danes, dogs come in a dizzying assortment of shapes and sizes. That makes them all too perfect for scientists who study how genes work.

In a recent essay in the scientific journal PLoS Biology, researchers from the National Human Genome Institute wrote about the major advances in understanding how dog genes translate to the rainbow of traits that make up the modern pooch.

More than 300 dog breeds are known around the world, including the 170 official American Kennel Club breeds. For hundreds of years, dog breeders have accidentally been creating a perfect model for studying genetics. Now science is reaping the benefits.

Not surprisingly, dogs of a single breed share many genetic similarities, according to the essay. A poodle has more genes in common with another poodle than it does with a border collie. By comparing genetic differences within breeds and between them, scientists can tease apart how genes control different traits, from short legs to a predisposition for disease.

The geneticists explain in their essay that dog breeds fall into five major groups: ancient and Asian dogs; hunting dogs and gun dogs; mastiffs and terriers; herding dogs and sight hounds; and mountain dogs. Dogs from a single cluster often share ancient genetic variations.

Dogs share many diseases with humans, so this kind of research is important for people as well as pooches. "Study of variation in dog species... help us hone in on the genomic factors for traits shared across species, including analogs for diseases that occur in the human population," the essay's senior author, Elaine Ostrander, told Live Science.

In other words, scientists have figured out what the rest of us pet lovers have known all along: Dogs are man's best friend.

Who are you calling shorty?

Dogs like dachshunds, basset hounds and corgis are famous for their stumpy little legs. Now researchers at the National Human Genome Research Institute in Maryland have figured out where the low-slung dogs get their stubby stems from, reports National Geographic News.

The researchers discovered that 19 short-legged dog breeds all share a single genetic mutation, which suggests that most short-legged dogs descended from a single stunted ancestor. It's possible that the gene could have arisen as many as 30,000 years ago, long before humans started breeding dogs for physical traits.

The researchers say the study, published in the journal Science, is proof that one little change to a gene can have a big impact. "There may just be a small number of major genetic changes that create all the different shapes and sizes of dogs," study co-author Heidi Parker said.

The short-legged gene is found in breeds from Shih Tzus and Scottish Terriers to Basset Hounds and Pekingese. For a (short) look at these squat pups, check out our gallery of stubby-legged dogs. Just remember, they're not short -- they're vertically challenged!

Source