Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 21, 1999
Publication Date: N/A
Interpretive Summary: One approach to fine mapping potential quantitative trait loci (QTL's) is to develop the bovine comparative map. The current linkage map in cattle contains fewer than 300 gene loci, thus making comparisons with the gene-rich human and mouse maps difficult. Development of the bovine map increases the density of markers associated with gene loci near the putative QTL, thereby allowing selection of positional candidate genes for further investigation. We used a PCR-based strategy to identify polymorphisms in non-coding regions of SDHA, presumed to be near a QTL for dairy form on bovine chromosome 27. Two single nucleotide polymorphisms (SNPs) were detected in an undefined intron SDHA. Genotypic data generated from a single SNP segregating in the MARC families was analyzed and integrated into the existing USDA/MARC linkage data set. The addition of SDHA to the bovine genetic map improves the bovine linkage map by extending coverage of the chromosome 20 linkage group 1.3 cM closer to the telomeric end of this chromosome.
The bovine SDHA cDNA (succinate dehydrogenase flavoprotein subunit A) has been cloned and sequenced, however this gene locus has not been placed on the genetic map. Primers were designed to detect single nucleotide polymorphisms from an intron of this gene. Sequence analysis of the SDHA 1202 bp products derived from 12 parental animals of the USDA MARC reference population revealed single nucleotide polymorphisms (SNPs) at sense strand position 863 (GGCCC A/G TGTGC) and position 978 (TCCCT C/G TCCCC). Both SNPs were detected only in animals of Bos Taurus x Bos Indicus descent. Genotypes from the reference population were generated by PCR-RFLP detection of the A/G-862 SNP in the 943 bp SDHA product. Linkage analysis revealed that the SDHA locus maps 1.3 cM distal to BMS521. This result extends coverage of the linkage group 1.3 cM closer to the telomeric end of bovine chromosome 20 (BTA20). The human orthologue of SDHA is localized to oHSA5p15, therefore the placement of bovine SDHA extends the synteny conservation between BTA20 and HSA5q13.3-p14.3 to 5p15.