|Johnson, Dwain - UNIV. FL, GAINESVILLE|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 24, 2005
Publication Date: August 25, 2005
Citation: White, S.N., Casas, E., Wheeler, T.L., Shackelford, S.D., Koohmaraie, M., Riley, D.G., Chase, C.C., Johnson, D.D., Keele, J.W., Smith, T.P. 2005. A new snp in capn1 extends the current tenderness marker test to include cattle of bos indicus, bos taurus, and crossbred descent. Journal of Animal Science. 83:2001-2008. Interpretive Summary: Genetic markers for the bovine CAPN1 gene have been previously published and associated with meat tenderness in cattle of Bos taurus descent. The current work supplies an additional marker associated with meat tenderness in Brahman cattle. This new marker is also associated with tenderness in Bos taurus cattle, as well as crossbred cattle. The wide applicability of the new marker provides a simple genetic test not restricted to Bos taurus cattle. The current work also demonstrates the extended usefulness of a previously published CAPN1 marker in some crossbred cattle, but not Brahmans. These results expand possibilities for using genetic markers to improve meat tenderness in many commercial herds, especially those including cattle of Brahman and/or crossbred descent.
Technical Abstract: Few have attempted genetic selection for improved beef tenderness despite the importance of this trait to consumer satisfaction and estimates that approximately half of the variation has a genetic basis. Two single nucleotide polymorphisms (SNP) in the CAPN1 gene have been described that could be used to guide selection in Bos taurus cattle (designated as markers 316 and 530), but neither marker segregates at high frequency in Brahman cattle. In this study, we examined three additional SNP in CAPN1 to determine if variation in this gene could be associated with tenderness in a large, multi-sire American Brahman population. One marker (termed 4751) was associated with shear force on postmortem day 7 (p<0.01), day 14 (p=0.015), and day 21 (p<0.001) in this population, demonstrating that genetic variation important for tenderness does segregate in Bos indicus cattle at or near CAPN1. Marker 4751 also was associated with shear force (p<0.01) in the same large, multi-sire population of cattle of strictly Bos taurus descent that was used to develop the previously reported SNP (referred to as the GPE cycle 7 population), indicating the possibility that one marker could have wide applicability in cattle of all subspecies backgrounds. To test this hypothesis, marker 4751 was tested in a third large, multi-sire cattle population of crossbred subspecies descent (including sire breeds of Hereford, Angus, Brangus, Beefmaster, Bonsmara, and Romosinuano, referred to as the GPE cycle 8 population). The highly significant association of marker 4751 with shear force in this population (p<0.0001) confirms the usefulness of marker 4751 in cattle of all subspecies backgrounds, including Bos taurus, Bos indicus, and crossbred descent. This wide applicability adds substantial value over previously released markers 316 and 530. However, marker 316, that had previously been shown to be associated with tenderness in the GPE cycle 7 population, also was highly associated with shear force in the GPE cycle 8 animals (p<0.001). Thus, marker 316 may continue to be useful in a variety of populations with high percentage Bos taurus backgrounds. An optimal marker strategy for CAPN1 in many cases will be to use both markers 316 and 4751.