CYP21 as a candidate gene for androstenone on boar taint

Abstract

The Cytochrome P450 steroid, 21 Hydroxylase (CYP21), is a positional candidate gene for boar taint caused by an excessive level of androstenone mainly in fat and muscle. CYP21 contains 9 introns and 10 exons and is located in the swine lymphocyte antigen (SLA) region on chromosome 7. Sequencing of four sires from an Australian mapping pedigree has revealed 36 SNPs. 22 of these are in non-coding regions, and those in coding regions do not cause changes in the amino acid sequence of the protein. However, a SNP at position 2329 (intron 7) could influence the use of a theoretical alternative splice site. Quantitative analysis has shown that segregation of this SNP in the sire families has no impact on androstenone levels. RT-PCR and sequencing have provided no evidence of the use of this alternative splice site in testis RNA. CYP21 can be excluded as the locus responsible for the SSC7 androstenone QTL.