Edge Over Cattle Diseases Through DNA Sequencing
By Luis Pons
April 4, 2003
Agricultural Research Service scientists in
Ames, Iowa, hope chromosome sequencing is the key that unlocks doors leading to
new tests and vaccines for cattle diseases.
Researchers at the
of Livestock Research Unit, part of the National Animal Disease Center (NADC) in Ames, used a DNA sequence
analyzer and collaborated with the University of Minnesota (U-M) to sequence the
chromosomes of microbes that cause Johne's disease and bovine brucellosis.
In addition, the sequencing of an agent that causes leptospirosis--a project
being done completely within the unit--has entered the final phase.
The analyzer, operated by ARS veterinary medical officer David Alt, allows
unit scientists to perform almost 800 reactions a day. It can automatically
analyze multiple runs of 96 DNA samples, making unattended 24-hour operation
Automated sequencing allows for rapid analysis of an organism's genes,
speeding identification of those linked to superior characteristics--or to
negative traits, such as susceptibility to disease.
Sequencing of Mycobacterium paratuberculosis, a microbe that causes
Johne's disease, was led by ARS microbiologist John Bannantine and U-M
pathogenomics scientist Vivek Kapur. Johne's is an intestinal disorder
characterized by diarrhea and weight loss in infected cattle. It is found in
seven percent of beef herds and 22 percent of dairy herds nationwide.
ARS microbiologist Shirley Halling and Kapur led sequencing work on
Brucella abortus. That microbe causes bovine brucellosis, a highly
contagious bacterial disease that induces late-term abortions and infertility
in cows, as well as undulant fever in humans.
The sequencing of Leptospira borgpetersenii serovar hardjo, a
cause of leptospirosis, is being led by ARS microbiologist Richard Zuerner.
Leptospirosis causes abortions, stillbirths and weak offspring in cattle and
swine, and it can reduce milk production in cows. It also affects many other
animals, including dogs.
More information about genome sequencing at NADC can be found in the
April 2003 issue
of Agricultural Research magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.