Food Safety

70 kiloDalton heat shock protein 2 (HSPA2) is expressed in the testis during the meiotic phase of spermatogenesis in humans and mice. Mutations in HSPA2 have been shown to cause sterility in male mice, while not affecting female reproductive capacity. Based on these comparative observations, HSPA2 is a candidate gene for influencing porcine male reproductive phenotypes. To initiate research assessing this possible relationship, the human HSPA2 sequence was used to identify a putative porcine HSPA2 sequence from public EST databases. This EST was used to isolate a Bacterial Artificial Chromosome (BAC) clone containing the porcine homolog of HSPA2. BAC DNA was subcloned, and the porcine HSPA2 locus was defined by sequence assembly and analysis. Extant genetic variation was identified by amplification and re-sequencing of HSPA2 (and flanking regions) with a series of overlapping primer pairs. In total, 11 Single Nucleotide Polymorphisms (SNPs) and 1 single base insertion/deletion were identified in the region spanning from 1062 bases upstream of the start codon to 672 bases downstream of the stop codon. None of the identified SNPs alter the amino acid sequence of the peptide. Two SNPs were converted into PCR-RFLP assays and used to genetically map the HSPA2 locus to chromosome 7, 87 cM, consistent with the syntenic relationship between Hsa14 and Ssc7. Future research can now be directed toward detecting associations between genetic variation and swine reproductive performance and other phenotypes.