Thursday, January 23, 2014

"Fawn Calf" Genetic Test Being Redesigned To Be More Accurate in Gelbvieh Pedigrees

MAGNUM - AMGV38
Picture from search.gelbvieh.org
On January 14th, Dr. Jon Beever of the University of Illinois sent a letter to the Board of Directors of the American Gelbvieh Association informing them that his lab had resolved issues with odd results when testing fullblood Gelbvieh animals with the DNA test for Contractural Arachnodactyly (CA, “fawn calf”). One of the oldest fullblood Gelbvieh bulls, Magnum (AMGV38) tested as a carrier of the CA abnormality, and several other Gelbvieh animals with little Angus influence tested as either affected or carrier.

Dr. Beever took several lines of action to evaluate what was producing the odd results and after DNA sequencing the region in the Gelbvieh animals found that the protein sequence was still functional in the Gelbvieh animals. But, the DNA base pair used in the diagnostic test was the same in affected Angus and normal Gelbvieh. Thus, the test was producing false positives in Gelbvieh animals.

Dr. Beever originally designed the test to minimize the false negative rate. His lab is currently in the process of redesigning the DNA test so that it accurately identifies carrier Angus animals without falsely calling normal Gelbvieh animals as carriers.

As announced by Rob Arnold, President of the American Gelbvieh Association, the Association is in the process of removing all CA carrier (CAC) statuses from animals wrongly identified as such.
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