DNA sequencer being loaded by geneticists Curt Van Tassell (left) and Tad
Sonstegard will increase the number of genetic markers available for screening
in livestock populations. Click the image for more information about
New Technique to Tap Bulls for Breeding
Suszkiw August 24, 2006
A project involving Agricultural Research Service (ARS) and collaborating scientists could open
the door to a new, genomics-based approach to identifying elite bulls.
Now carried out by the artificial insemination (AI) industry, progeny
testing characterizes the genetic merit of a bull. But progeny testing is
time-consuming and expensive. Each year, AI organizations test 1,200 Holstein
dairy bulls at a cost of about $30 million.
Cutting test costs while increasing the rate of genetic improvement in
dairy cattle could help make the U.S. germplasm industry even more competitive
in the world market, according to
Van Tassell. He's a geneticist working with the ARS
Functional Genomics Research Unit and the ARS
Improvement Programs Laboratory, both in Beltsville, Md.
Records on performance and conformation are combined with pedigree
information using sophisticated statistical methods to determine the genetic
merit of animals used for breeding. But Van Tassell and ARS collaborators
Wiggans are investigating an approach called "genome-enhanced selection"
which could replace progeny testing and cost around $500 per bull.
Central to the approach is obtaining information on DNA sequence
variations, or genetic markers, called single nucleotide polymorphisms (SNPs).
Efforts are under way to develop a test to allow close examination of 55,000
SNPs from a select group of 4,000 animals representing several dairy breeds and
an ARS research population.
The scientists will then correlate the SNP data to observable, or
phenotypic, traits of interest so that eventually dairy producers can use
information derived from the markers to selectively breed animals based on
Collaborating with the Beltsville team are professors Jerry Taylor
with the University of Missouri-Columbia
and Stephen Moore with the University of
Alberta-Edmonton, Canada; and Illumina,
Inc., of San Diego, Calif.
The ARS labs have cooperative agreements with the
National Association of Animal Breeders
of Columbia, Mo., and Merial Limited of
Duluth, Ga. The project also received funding from the
National Research Initiative.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.