Identification of Quantitative Trait Loci Affecting Meat Quality in a Berkshire by Yorkshire 3 Generation Family
M. Malek, J.C.M. Dekkers, H.K. Lee, T.J. Baas, K. Prusa, E. Huff-Lonergan, M.F. Rothschild
Departments of Animal Science and Department of Food Science and Human Nutrition, Iowa State University, Ames 50011
The techniques of molecular genetics and gene mapping have rapidly progressed. These methods, coupled with advances in human genetics, have opened new vistas for investigators wishing to identify genes that control quantitative traits (quantitative trait loci or QTL). A three-generation resource family was developed at Iowa State University to study individual effects of genes on meat quality traits in pigs. This family was developed using two Berkshire grand sires and nine Yorkshire grand dams. These F0 animals were mated to produce nine F1 litters. From the F1 litters a total of 65 matings were made in four seasons to produce a total of 525 F2 animals. All F2 animals were phenotyped for birth weight, 16 day weight, growth rate, back fat, loin eye area, drip loss, water holding capacity, firmness, color, marbling, percent cholesterol, ultimate pH, fiber type and several sensory panel and cooking traits. All animals were genotyped for 125 microsatellite markers covering the entire porcine genome. Linkage analysis was performed using CRIMAP version 2.4 software (Green et al. 1990). The regression interval mapping method (Haley et al. 1994) was used to analyze the data. Permutation tests were performed to determine chromosome and experiment-wise significance levels for hypothesis testing. Significant QTL at the chromosome wide 5% level were detected for growth (chromosomes 1, 2, 3, 4, 6, 7, 8, 9, 11, 13, 14, 15), back fat (chromosomes 1, 4, 5, 6, 7, 12, 13, 14, 18) and meat quality traits (chromosomes 1, 2, 4, 5, 6, 8, 10, 11, 12, 13, 14, 15, 17, 18, X). Additional marker analysis and examination for positional candidate genes is underway. This work was supported by an industry consortium consisting of National Pork Producers Council, Iowa Pork Producers Association, Iowa Purebred Swine Council, Babcock Swine, Danbred USA, DEKALB Swine Breeders, PIC, Seghers genetics USA, and Shamrock Breeders.
Key words: quantitative trait loci, meat quality
Presented at ASAS annual meeting in Baltimore 2000
Reprinted by permission of the American Society of Animal Science