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New test should ensure no more Mini-MoosDES MOINES, Iowa (AP)--Mini-Moo, a five-year-old Angus who lives at Iowa State University's Beef nutrition Farm, was born with a condition known as "long head dwarfism." This genetic mutation caused her legs to stop growing before the rest of her was fully grown. However, Angus cattle like Mini-Moo may become a thing of the past because of a new test for the mutation developed by James Reecy, an associate professor in animal science at Iowa State University. Reecy and a research team identified the genetic marker for the long head dwarfism mutation and developed a test to find it. "If this technology is adopted by (Angus cattle) producers, in theory, we should never see another case of this form of dwarfism," said Reecy, who currently is on sabbatical in England. It took Reecy six years to collect the genetic material he needed to identify the mutation. He worked with researchers from Washington State University, the University of Nebraska, the University of Liege in Belgium and cattle breeders in Michigan, Montana and Washington to collect the genetic material. Long head dwarfism in Angus cattle has been a problem for producers for many years, and has been "in the gene pool probably for centuries," Reecy said. The genetic mutation affects bones that have growth plates, such as the legs. Bones in the head grow normally while leg bones don't develop, leading to shortened legs that make the head look long. Both parents--the bull and the cow--need to have the mutation for the disease to pass it along to their offspring. Reecy said the American Angus Association contacted him to see if he could find the mutation. "I jumped at the chance because understanding gene function is an interest of mine," he said. "Any chance that I can do this to help cattle breeders and producers, so much the better." Bryce Schumann, chief executive for the American Angus Association, said the association has had a monitoring program for genetic defects for 30 years. "We've had a long-standing policy of monitoring for defects and informing our members when these defects occur," Schumann said. Carriers of the long head dwarfism gene are listed on the Angus Association's Web site, www.angus.org. A test developed years ago by another Iowa State researcher, Jay Lush, identified bulls that carried the dwarfism genetic defect. Although Lush's test was a huge breakthrough, Reecy said, there was no test for females. Lush's bull test dramatically lowered the number of long head dwarfism cases, but in 2002 six long head dwarf calves were born on a ranch in Washington state. The Angus Association asked Reecy to investigate. He and researchers Bishnu Kumar and James Koltes at Iowa State started collecting DNA from the parents of the dwarfs and from all of the ancestors they could find. That took six months. Next, the group looked for genes in Angus cattle dwarfism in other breeds and in all mammals. A breakthrough came when the group found a paper on dwarf mutation in rats similar to long head dwarfism in Angus. About two years ago, the researchers found what they believed to be the causal mutation, or the change in the DNA responsible for the dwarfism. Since then, Reecy and the researchers have been proving their findings and developing a test for the mutation in the gene known as "PRKG2." Their new test allows producers to test--easily and inexpensively--for long head dwarfism in males and females. Reecy, however, suspects the disease may not be eliminated right away. "There's always a chance that producers will use the test for several years or so and, when no one gets a case, they might stop using it," Reecy said. That means in 10 years or so, some cow that never got tested will have a calf with long head dwarfism, he said. Reecy is spending his sabbatical in England learning about evaluating livestock genomes. "With the (genetic) sequencing of the cow, chicken and the soon-to-be-completed pig, there is a wealth of information that needs to be analyzed," Reecy wrote in an e-mail. Reecy said he wants to develop a national surveillance network to identify the mutations that underlie genetic diseases in cattle. "Currently, there are a lot of genetic diseases in cattle that have not yet had the causal mutation identified," he said. 6/30/08 Date: 6/25/08
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