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United States Department of Agriculture

Agricultural Research Service

Title: DETECTION OF QUANTITATIVE TRAIT LOCI FOR MARBLING AND BACKFAT IN WAGYU X LIMOUSIN F2 CROSSES USING A CANDIDATE GENE APPROACH

Authors
item De, S - WASH STATE U PULLMAN
item Macneil, Michael
item Wu, X - WASH STATE U PULLMAN
item Michal, L - WASH STATE U PULLMAN
item Xiao, Q - WASH STATE U PULLMAN
item Garcia, M - WASH STATE U PULLMAN
item Griffin, K - WASH STATE U PULLMAN
item Gaskins, C - WASH STATE U PULLMAN
item Reeves, J - WASH STATE U PULLMAN
item Busboom, J - WASH STATE U PULLMAN

Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 15, 2004
Publication Date: June 15, 2004
Citation: De, S., Macneil, M.D., Wu, X.L., Michal, L.L., Xiao, Q., Garcia, M.D., Griffin, K.B., Gaskins, C.T., Reeves, J.J., Busboom, J.R. 2004. Detection of quantitative trait loci for marbling and backfat in wagyu x limousin f2 crosses using a candidate gene approach. Western Section of Animal Science Proceedings 55:95-98.

Interpretive Summary: Marbling commonly describes the presence of white flecks or streaks of fatty tissue between the muscle fibers in meat. Backfat refers to the amount of fat over the animal's back, usually measured between the twelfth and thirteenth rib in beef. Both traits have attracted a great deal of interest, since these two quantitative traits affect carcass quality and value in beef cattle. In this study, 247 F2 Wagyu x Limousin animals with recorded phenotypes for marbling and backfat were genotyped for four previously identified candidate gene markers: thyroglobulin (TG), leptin (LEP), diacylglycerol O-acyltranferase (DGAT1) and growth hormone 1 (GH1). Only the DGAT1 gene had a significant effect, and then only on backfat thickness. Otherwise, our results indicate that not all genes previously identified as affecting marbling and backfat significantly impacted these phenotypes in crosses between Wagyu and Limousin. Given the variability of these traits and their economic importance in the marketing of beef in the U.S., further effort to identify QTL affecting marbling and backfat in crosses of Wagyu and Limousin is warranted.

Technical Abstract: Marbling commonly describes the presence of white flecks or streaks of fatty tissue between the muscle fibers in meat. Backfat refers to the amount of fat over the animal's back, usually measured between the twelfth and thirteenth rib in beef. Both traits have attracted a great deal of interest, since these two quantitative traits affect carcass quality and value in beef cattle. In this study, 247 F2 Wagyu x Limousin animals with recorded phenotypes for marbling and backfat were genotyped for four candidate gene markers: thyroglobulin (TG), leptin (LEP), diacylglycerol O-acyltranferase (DGAT1) and growth hormone 1 (GH1) genes. The markers were assayed on a C/T substitution in TG, a C/T substitution in LEP, a C/A substitution in DGAT1 and an MspI polymorphism in GH1, respectively. The backfat measurements on those animals varied from 0.1 to 1.3 inches and marbling scores ranged from 4 to 9.5. Frequencies of allele C in TG, allele C in LEP, allele A in DGAT1 and allele 1 in GH1 were 0.61, 0.68, 0.58 and 0.10, respectively. Analysis of variance using a generalized linear model did not show any significant differences among genotypes in LEP and GH1 genes. However, the DGAT1 gene had a significant additive effect on backfat (P = 0.036), while the TG gene showed a dominant effect on marbling that approached significance (P = 0.061). Our results indicate that not all genes previously identified as affecting marbling and backfat significantly impacted these phenotypes in crosses between Wagyu and Limousin. Given the variability of these traits and their economic importance in the marketing of beef in the U.S., further effort to identify QTL affecting marbling and backfat in crosses of Wagyu and Limousin is warranted.

Last Modified: 7/11/2014
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