Annotation of Sheep Keratin Intermediate Filament Genes and Their Patterns of Expression

The study identified nine novel sheep keratin intermediate filament (KRT) genes, increasing the known active genes to 17, similar to humans. It highlighted species-specific differences, such as the absence of KRT37 and the presence of KRT87 in sheep. Phylogenetic analysis showed consistency in sequence conservation across sheep, cattle, and humans, but differences were noted in the expression patterns of six ovine KRT genes compared to human orthologs. Specifically, KRT40, KRT82, and KRT84 were expressed only in the fibre cuticle, while KRT32, KRT35, and KRT85 were found in both the cuticle and fibre cortex. The remaining 11 genes were expressed solely in the cortex. These findings were discussed in relation to their roles in wool and hair development and the unique characteristics of the fibres produced.