Genus and Species. Sus scrofa. Locus. Pig Progesterone Receptor ( PGR) gene. Source and Description of Primers. Oligonucleotide primers were designed from a partial pig PGR cDNA sequence (Genbank accession no. S49016) with inferred intron-exon boundary information from humans (Misrahi et al., 1993). The primers were designed to span the intron between exons 7 and 8 of the PGR gene.