Identifying Variation in the U.S. Bovine Prion
January 22, 2007
Do genes affect bovine spongiform
encephalopathyalso known as BSE, or "mad cow" disease? Are some
cattle more susceptible than others?
To address these and other questions, Agricultural Research Service (ARS)
scientists at the
Meat Animal Research Center in Clay Center, Neb., have sequenced the bovine
prion gene (PRNP) in 192 cattle that represent 16 beef and five dairy
breeds common in the United States.
This work, partially funded by a grant from the U.S. Department of
Agriculture's Cooperative State Research,
Education and Extension Service, is expanding the understanding of how the
BSE is a fatal neurological disorder characterized by prionsproteins
that occur naturally in mammalsthat fold irregularly. Molecular biologist
Clawson and his Clay Center colleagues are examining PRNP variation
in order to learn if and how prions correlate with BSE susceptibility.
From the 192 PRNP sequences, Clawson and his colleagues have
identified 388 variations, or polymorphisms, 287 of which were previously
unknown. Some of these polymorphisms may influence BSE susceptibility in
Comparing PRNP sequences from infected and healthy cattle may enable
researchers to identify genetic markers in the prion gene that predict BSE
susceptibility. In addition to PRNP, the team is currently sequencing
several closely related genes, which will also be tested for their association
The prevalence of BSE in the United States is extremely low, but this
research could improve understanding of the disease and prepare the cattle
industry to respond if another prion disease should arise in the future.
more about this research in the January 2007 issue of Agricultural
ARS is the USDA's chief scientific