Refined mapping of quantitative trait loci for somatic cell score on BTA02 in the German Holstein.
The aim of this study was to more precisely map a previously reported quantitative trait locus (QTL) affecting somatic cell score on Bos taurus autosome 2 by increasing the number of markers fourfold, analysing more families and exploiting within-population linkage disequilibrium (LD). A granddaughter design of 10 German Holstein grandsire families with 1121 progeny tested sons was used. Twenty-six markers with an average marker spacing of 3.14 cM were genotyped along 81.6 cM. Linkage analysis (LA) was performed using variance-component methodology. The incorporation of LD was first done using variance-component methods followed by regression on marker alleles. LA revealed genome-wide significance (LOD > 3) at 15 contiguous marker-intervals, with the maximum test-statistic between DIK2862 and BMS778 and a 1-lod drop-off interval of 38 cM. While the variance-component methods could not detect any LD, two individual markers with a significant effect (ILSTS098, p < 0.05; BMS778, p < 0.01) were found by regression analysis. Compared with previous results QTL-localisation was substantially narrowed; further fine-mapping should focus on the close vicinity of BMS778.
Research Institute for the Biology of Farm Animals, Research Unit: Genetics and Biometry, 18196 Dummerstorf, Germany.
C
C
Baes
I
I
Goertz
M
M
Mayer
C
C
Weimann
Z
Z
Liu
F
F
Reinhardt
G
G
Erhardt
N
N
Reinsch
D000818:Animals; D001824:Body Constitution / Q000235:genetics*; D001947:Breeding / Q000379:methods*; D002417:Cattle / Q000235:genetics*; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian / Q000235:genetics*; D003612:Dairying / Q000379:methods*; D005819:Genetic Markers / Q000235:genetics; D005858:Germany; D015810:Linkage Disequilibrium; D040641:Quantitative Trait Loci / Q000235:genetics*; D012044:Regression Analysis
D005819:Genetic Markers