Submitted to: Mammalian Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 19, 1996
Publication Date: N/A
Interpretive Summary: A prerequisite to identifying quantitative trait loci (QTL's) is the development of a genetic linkage map containing enough informative DNA markers to maximize genome coverage. Previous genetic maps of BTX contained only fifteen informative DNA markers each, and thereby, lacked sufficient DNA marker density and genome coverage to be used for identfying QTLs within and between breeds of cattle. We used a chromosome specific libraries to systematically increase DNA marker density for the short arm of BTX. Seven new DNA markers were identified. Genotypic data from these seven markers and 23 previously unlinked markers was generated from the MARC families and integrated into the existing USDA/MARC's BTX linkage group. The number of linked ms markers was increased from 26 to 56. This BTX linkage map spans 158 cM (ave. interval of 2.8 cM). In addition, the linkage map was integrated with the physical map to define the extent of coverage, and identify a genetic interval that contains the centromere of BTX. The nearly four-fold improvement in informative marker density of BTX provides a genetic map which will enhance QTL analysis within and between breeds of cattle.
Genotypic data for 56 microsatellites (ms) generated from maternal full sib families nested within paternal half sib families, was used to construct a linkage map of the bovine X chromosome (BTX) that spans 158 cM (ave. interval 2.8 cM). The linkage map contains 30 new ms markers; seven generated from a BTXp library. The genotypic data from these 30 ms was merged with 26 previously linked markers to more than double the number of informative BTX markers. A male specific linkage map of the pseudoautosomal region was also constructed from five Type II loci at the distal end of BTXq. Four informative probes physically assigned by fluorescence in situ hybridization defined the extent of coverage, confirmed the position of the pseudoautosomal region on the q-arm, and identified a 2.1 cM marker interval that contains the centromere of BTX.