Identification of a 3.7-Mb region for a marbling QTL on bovine chromosome 4 by identical-by-descent and association analysis.
QTL mapping for growth and carcass traits was performed using a paternal half-sib family composed of 325 Japanese Black cattle offspring. Nine QTL were detected at the 1% chromosome-wise significance level at a false discovery rate of less than 0.1. These included two QTL for marbling on BTA 4 and 18, two QTL for carcass weight on BTA 14 and 24, two QTL for longissimus muscle area on BTA 1 and 4, two QTL for subcutaneous fat thickness on BTA 1 and 15 and one QTL for rib thickness on BTA 6. Although the marbling QTL on BTA 4 has been replicated with significant linkages in two Japanese Black cattle sires, the three Q (more marbling) haplotypes, each inherited maternally, were apparently different. To compare the three Q haplotypes in more detail, high-density microsatellite markers for the overlapping regions were developed within the 95% CIs (65 markers in 44-78 cM). A detailed haplotype comparison indicated that a small region (<3.7 Mb) around 46 cM was shared between the Qs of the two sires, whose dams were related. An association of this region with marbling was shown by a regression analysis using the local population, in which the two sires were produced and this was confirmed by an association study using a population collected throughout Japan. These results strongly suggest that the marbling QTL on BTA 4 is located in the 3.7-Mb region at around 46 cM.
Shirakawa Institute of Animal Genetics, Odakura, Nishigo, Fukushima 961-8061, Japan.
K
K
Yokouchi
Y
Y
Mizoguchi
T
T
Watanabe
E
E
Iwamoto
Y
Y
Sugimoto
A
A
Takasuga
D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D001823:Body Composition; D002417:Cattle / Q000235:genetics*; D033481:Chromosomes, Mammalian; D005260:Female; D008297:Male; D008460:Meat; D040641:Quantitative Trait Loci