Identification of four new gene members of the KAP6 gene family in sheep

KAP6 is a high glycine-tyrosine keratin-associated protein (HGT-KAP) family. This family is thought to contain multiple genes. In this study, we used a KRTAP6 coding sequence to search the Ovine Genome (v3.1) and identified five homologous regions (R1–R5). All these regions contained an open reading frame, and they were either identical to, or highly similar to, sheep skin Expressed Sequence Tags (ESTs). Phylogenetic analysis revealed that R1–R5 were clustered with KAP6 sequences from different species and formed a group distinct to other HGT-KAPs. R1 was very similar to the characterised KRTAP6-1 sequence, but the remaining genes appeared to be new. PCR primers were designed to amplify and confirm the presence of these new genes. Amplicons were obtained for all of the 96 sheep investigated. Six, five, three and six PCR-SSCP patterns representing six, five, three and six DNA sequences were observed for KRTAP6-2 to KRTAP6-5 respectively. KRTAP6-2 and KRTAP6-4 had five and three SNPs respectively. Three SNPs and a 45-bp insertion/deletion were detected for KRTAP6-3, and five SNPs and an 18-bp insertion/deletion were identified for KRTAP6-5. Allele frequencies for these KAP6 genes differed between Merino and Romney sheep.