Rapid communication: mapping of the bovine stearoyl-coenzyme A desaturase (SCD) gene to BTA261.

Genus and Species. Bos indicus and Bos taurus. Locus Name. Bovine stearoyl-coenzyme A desaturase (SCD). Source and Description of Primers. Primers were designed that amplified a 135-bp region in SCD exon 6. Sequences from human (GenBank accession number Y13647), rat (AB003357), mouse (M21285), and pig (Z97186) were aligned to identify a conserved region in which to design the primers. The forward primer was 5′ YGA GGG CTT CCA CAA CTA C 3′ and the reverse primer was 5′ ACT TTC TTC CGG TCA TAR GC 3′. Method of Mapping. Primers were used to screen a bovine artificial chromosome (BAC) library (Cai et al., 1995), resulting in identification of a single clone. Screening the BAC library was performed by PCR containing 1× Taq buffer and 1.5 mM MgCl2. Conditions for PCR were 35 cycles of 30-s denaturing at 94°C, 30s annealing at 58°C, and 30-s extension at 72°C. The PCR product was sequenced to validate the identity of the clone. All reactions were performed on a Techne MW-2 (Techne, Princeton, NJ). The sequence aligned completely with bases 886 to 1,017 of the bovine stearoyl-coenzyme A desaturase cDNA (GenBank accession number AF188710) and was 91% homologous to the porcine (Z97186) and murine (NM_009127) SCD1 cDNA. A GT repeat was found when the BAC clone was digested with Sau3AI. Primers were designed to amplify a 178-bp segment encompassing this repeat. The forward microsatellite primer was 5′ TTC TGC TGT ATA TCG AAG TA 3′ and the reverse microsatellite primer was 5′ TTA TCA GAT GCA AGC TAT T 3′. For the microsatellite, reagents were the same as those for screening the BAC library, except the forward primer was end-labeled with [γ-32P]ATP and the annealing temperature was 52°C. The BAC clone that contained the SCD gene was mapped with the fluorescence in situ hybridization procedure described by Pinkel et al. (1986).