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Validation of DNA markers for Tenderness    

A genotyping assay for French Cattle Breeds

Validation of DNA Markers and Development of Genetic Predictions for Tenderness in Limousin Cattle

Presented to the International Limousin Conference France, September 2000

By Kent Anderson of North American Limousin Foundation

The National Cattlemen's Beef Association, along with NALF and approximately ten other breeds, are involved in an industry wide research project designed to validate candidate DNA markers for tenderness and develop genetic predictions. Over the next two years, NALF plans to collect tenderness data in the form of Warner-Bratzler shear tests and taste panel evaluations from approximately 800 head of Limousin cattle. When completed, this will be the U.S. beef industries most extensive effort to date to help genetically ensure acceptable eating experiences for the consuming public.

Summary

In addition to the research projects discussed here, NALF has and will continue to conduct in-house research to monitor the evolution of the Limousin breed in the U.S. Ultimately, information generated from NALF research efforts is intended to help give Limousin breeders worldwide, a competitive advantage in supplying genetic inputs to meet the needs of consumers.

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A First Genotyping Assay of French Cattle Breeds based on a New Allele of the Extension Gene Encoding the Melanocortin-1 Receptor (Mc1r)

Presented to the International Limousin Conference, France 2000

Written by Francois Rouzauda), Juliette Martina), Paul Francois Galleta), Didier Delournea), Valerie Goulemot-Legerc), Yves Amiguesc), Francois Menissierd), Hubert Leveziela) b), Raymond Juliana), Ahmad Oulmoudena).

a) Unite de genetique moleculaire animale, UC1061 (Universite/INRA) - Universite de Limoges, 87060 Limoges.
b) Last adress: Unite de genetique biochimque et cytogenetique - UR339 - INRA - 78352 Jouy-en-Josas
c) Laboratoire d'analyses genetiques pour les especes animales (LABOGENA) - INRA - 78352 Jouy-en-Josas
d) Station de genetique quantitative et appliquee - UR337 - INRA - 78352 Jouy-en-Josas


Abstract The seven transmembrane domain melanocortin-1 receptor (Mc1r) encoded by the coat colour extension gene (E) plays a key role in the signalling pathway of melanin synthesis. Upon the binding of agonist (melanocortin hormone α-MSH) or antagonist (Agouti protein) ligands, the melanosomal synthesis of eumelanin and/or phaeomelanin pigments is stimulated or inhibited, respectively. Different alleles of the extension gene were cloned from unrelated animals belonging to French cattle breeds and sequenced. The wild type E allele was mainly present in Normande cattle, the dominant ED allele in animals with black colour (i.e. Holstein), whereas the colour (Blonde d'Aquitaine, Charolais, Limousin and Salers).

A new allele, named E1, was found in eith homozygous (E1/E1) or heterozygous (E1/E) individuals in Aubrac ans Gasconne breeds. This allele displayed a 4 amino acid duplication (12 nucleotides) located within the third cytoplasmic loop of the receptor, a region known to interact with G proteins. A first genotyping assay of the main French cattle breeds is described based on these four extension alleles.
 

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Last updated: October 09, 2000 .