Over 80 keratin-associated protein (KAP) genes in 27 families have been identified in the human genome (1). These families, each comprising 1-12 members, are classed into three superfamilies according to their amino acid composition. There are 40, 34 and 14 genes in the high sulphur (HS), ultra-high sulphur (UHS) and high glycine-tyrosine (HGT) families, respectively (2). In sheep, however, only 34 genes in nine families have been reported and none corresponds to members from recently recognised human KAP families (KAP11-KAP27).
The high level of conservation between the human and sheep analogues of several families indicates that cDNA sequence homology can be used for identifying unknown ovine KAP cDNA. In this work, cDNA and protein sequences of all the known KAP genes from human, cattle and, occasionally, other species were used to BLAST an in-house cDNA contiguous sequence library. Ovine cDNA with the highest homology were subsequently used for whole length sequence alignments with known members of the same family or members of other gene families showing adequate similarities.
Most of the 75 sequences identified encoded full length proteins. In addition to confirming almost all previously reported ones, 43 sequences representing novel ovine KAP genes were revealed. Twenty five were members of 10 previously unknown ovine KAP gene families. Altogether, 32 (12 new), 34 (26 new) and nine (five new) members for the ovine HS, UHS and HTG superfamilies respectively have been annotated. The results indicate that many KAP families in humans and sheep are represented by similar numbers of expressed genes. This progress in the annotation of KAP genes in sheep provides the sequence information necessary to localise their expression and investigate protein-interactions involved in wool fibre formation. (286 words)

References:
1. Rogers, et al (2008) Br J Dermatol 159:725-729.
2. Rogers, et al (2006) Int Rev Cytol 251:209-263.