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Bovine Genome To Help Cattle and Humans
By David Elstein
September 20, 2002
In the near future, scientists may
be able to improve production traits in cattle--and possibly help provide
solutions to certain human health problems--thanks to the mapping of the bovine
genome by scientists with the Agricultural
Research Service and their colleagues around the world.
The project began in spring 2000 when Steven M. Kappes, director of ARS'
Roman L. Hruska U.S. Meat Animal Research
Center in Clay Center, Neb., began contacting labs around the world to
develop a Bacterial Artificial Chromosome (BAC) map. Bacteria--and more
specifically, bacterial chromosomes--are used as hosts for pieces of bovine
chromosomes. The bacterial hosts are used to generate many identical copies of
a piece, or clone, of cattle DNA. The BAC map will help scientists identify
genes that affect production traits in farm animals and will help them sequence
the bovine genome.
The first step is fingerprinting each of 280,000 BAC clones. This is done by
cutting DNA from a BAC clone into pieces and separating the fragments on a gel.
Researchers use the fingerprint pattern of the different fragments to identify
overlapping BAC clones. A BAC map is the collection of overlapping clones that
represent the entire bovine genome.
The second step, which can occur simultaneously with the fingerprinting, is
sequencing both ends of all 280,000 clones. The scientists will combine the end
sequencing and fingerprinting information to determine the overlapping BAC
So far, 249,000 of the 280,000 cattle BAC clones have been fingerprinted,
and the end- sequencing effort is under way. The completion date for the bovine
BAC map is February 2003.
Once the project is complete, scientists may be able to more accurately
select genetically superior animals for specific purposes, such as lean beef,
milk production or reduced feed requirements. This research may also help the
medical community, since cattle and humans have many of the same genes.
Scientists will be able to compare the genetic maps of each species to possibly
find cures for diseases.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.