| Dog DNA
Study Yields Clues to Diverse Size of Breeds
Scientists First to Isolate a Single Gene Common to All
Small Dogs
ROCKVILLE, Md., April 5 /PRNewswire/ -- From the
smallest Chihuahua to the largest Great Dane, dogs
dramatically vary in size, much more than most other
animals. Now scientists have discovered a genetic basis
for this diversity.
A new study published in tomorrow's edition of the
research journal Science reveals a genetic marker that
may determine whether dogs are big or small, and helps
answer a burning question in genetics -- how could dogs
as a species have such a tremendous variation in size?
"This study is a major milestone in canine genetics,
made possible by the help of thousands of dog owners
around the world. Together with a team of leading
international researchers, we have precisely located the
major gene that produces our miniature breeds," said
co-author Paul G. Jones, PhD, a genetics researcher at
Mars -- a world leader in pet care that has been
researching canine genetic science for the last seven
years.
Dogs were one of the earliest animals to be domesticated
more than 15,000 years ago, although people and wolves
have coexisted for some 400,000 years. While all dogs
originated from wolves, which are of a fairly standard
size and appearance, modern dog breeds display a wide
diversity of traits, including size. The genetic origin
of this diversity has baffled scientists, who have been
trying to explain how and why size difference occurred
so rapidly in dogs. It is now thought that a change in
the gene detailed in the published paper resulted in the
appearance of small dogs in the population many
thousands of years ago. It is likely that people soon
saw the benefits of smaller dogs, for example for
protecting food stores from vermin or catching small
game. This further strengthened the bond between people
and dogs and led to increasing popularity of smaller
dogs as companions.
The international team of researchers -- ranging from
scientists at the National Human Genome Research
Institute, Cornell and other leading universities in the
U.S. to Mars scientists in the United Kingdom -- used
3,200 dog DNA samples provided by Mars Incorporated,
which holds the most comprehensive canine genetic
database in the world. This has been built up with the
help of pet owners who consent to their pets providing
saliva and blood samples for the database. Mars' genetic
data allowed the study to fill the gap between giant and
miniature breeds ensuring coverage across the entire
range of sizes of breeds we have today.
"These findings are just the tip of the iceberg in
canine genetics," Jones said. "We are well on our way to
identifying additional genes that can provide valuable
insights into our pets."
With the dog genome now fully mapped, scientists are
discovering a range of potential benefits of DNA-based
information on man's best friend.
"The ability to isolate a specific genetic marker in
such a quick and effective manner has tremendous
implications for the future," Jones said. "Applications
of this cutting-edge science could be used to develop
products that will benefit the health of pets -- for
example, developing individualized preventative care
plans for dogs that are susceptible to certain diseases
will help pet owners and veterinarians. In addition,
genetic information about size and behavioral traits,
such as trainability and temperament could also help
veterinarians identify the most lifestyle-appropriate
pet for an owner. "
Mars is continuing its commitment to canine genetic
science with ongoing investigations to better understand
the makeup of a dog's DNA to help benefit the lives of
dogs and pet owners.
Source: Sutter NB, et al. A single IGFI allele is a
major determinant of small size in dogs. Science. April
6, 2007.
About Mars Inc.
Mars, Incorporated, is a privately-held company that
produces some of the world's leading confectionery,
food, petcare, beverage, and health & nutrition
products, and operates in more than 65 countries.
Headquartered in McLean, Virginia, Mars, Incorporated
employs more than 9,000 associates in the United States
and 40,000 associates worldwide with 37 manufacturing
facilities nationally and more than 100 manufacturing
facilities globally. The company's global sales exceed
$18 billion annually.
About Mars Veterinary(TM)
Mars Veterinary is the newest division of MARS(R)
Incorporated, a company known for innovative consumer
and pet food brands that are trusted by people around
the world. Mars Veterinary is developing sophisticated
genetic tests that allow pet owners, veterinarians and
care providers to gain insight into the genetic make up
of their individual dog. It is reaching new frontiers in
canine genomic science, discovering important genetic
markers that will help identify breed mixes,
predispositions to specific diseases, and determinants
of physical and behavioral traits. Through research into
pet genetics, Mars Veterinary is dedicated to
revolutionizing personalized pet care by strengthening
the bond between people and their canine companions. For
more information, visit http://marsveterinary.com/ .
About Science
Science is the world's leading journal of original
scientific research, global news and commentary. The
journal is a publication of the American Association for
the Advancement of Science (AAAS).
Dog Facts
Dogs have one of the widest variations in size of any
species. The adult bodyweights of the largest breeds are
up to 70 times more than those of the smallest breeds.
According to the American Kennel Club, in 2006 the most
popular large-breed dogs in the USA were the Labrador
Retriever, the German Shepherd Dog and Golden
Retrievers; the most popular small-breed dogs were
Yorkshire Terriers, Dachshunds and Shih Tzus.
Source: Mars Inc.
Web site: http://marsveterinary.com/
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