Meat from cattle having two copies of the
myostatin gene. This cut has more meat, less fat, and less marbling than meat
from cattle having no copies or one copy of the gene. Click the image for
more information about it.
Read the
magazine
story to find out more.
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Sorting Out
the Genes Behind Leaner Beef
By Erin Peabody
July 19, 2004 A lean cut of beef, low in saturated
fat, that's also flavorful and tender? Sound too good to be true?
It may not be, according to animal scientists and geneticists with the
Agricultural Research Service who are
studying cattle genes that may contribute to leaner cuts of beef. They've been
especially interested in a gene that codes for the protein known as myostatin.
Myostatin limits muscle growth in mammals, including humans. But when the
gene responsible for producing the protein is altered or suppressed somehow,
the result is enhanced muscle growth and reduced fat deposition. Researchers
achieve this muscularity in cattle through selective breeding strategies.
Scientists at the ARS Meat Animal Research Center (MARC) in Clay Center, Neb., have found
that a key benefit of inactivated myostatin in cattle is the creation of beef
that's tender and lower in saturated fat. All cuts of beef from cattle
possessing the inactivated myostatin have improved tenderness, according to
MARC food technologist Tommy L. Wheeler.
Despite the promise of breeding systems that manipulate myostatin,
researchers are aware of possible drawbacks. When animals inherit copies of the
altered myostatin gene from both parents--instead of just one--they are born
with a condition that's known as double-muscling.
Double-muscled animals often require additional birthing assistance and
sometimes Caesarean delivery, according to MARC animal geneticist Timothy P.L.
Smith. These cows may also experience reduced fertility and lower stress
tolerance.
ARS researchers, including Michael D. MacNeil, an animal geneticist at the
agency's Fort Keogh Livestock and
Range Research Laboratory in Miles City, Mont., are looking to other
breeds--like Limousin and Charolais--that are also well-muscled and trim. These
cattle may achieve their lean physiques through the collective action of
several genes, each exerting a small effect.
Read
more about the research in this month's issue of Agricultural Research
magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.
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