Variation in the ovine KAP8-1 gene affects wool fibre uniformity in Chinese Tan sheep

Abstract

Chinese Tan sheep are known for producing ‘spring-like’ crimped wool fleeces that consist of both fine wool fibres (non-medulated) and heterotypic wool fibres (frequently medulated). The genetic basis of these unique characteristics is poorly understood. Wool fibres are comprised of hard alpha-keratins embedded in keratin-associated proteins (KAPs). Variation in the KAP8-1 gene (KRTAP8-1) was investigated in Chinese Tan sheep, and the effect of variation in the gene on four key wool traits [mean fibre diameter (MFD), fibre diameter standard deviation (FDSD), coefficient of variation of fibre diameter (CVFD) and mean fibre curvature (MFC)] was investigated for both the fine and heterotypic wool fibres. Three previously identified ovine KRTAP8-1 variants (A, D and E) were detected, but two other previously identified variants (B and C) were not present in these Tan sheep. Of the six genotypes (AA, AD, AE, DD, DE and EE) observed, the effect of the genotype on wool traits were analysed for the three (AA, AE and EE) where the genotype frequency was greater than 5%. Genotype was found to have an effect (P = 0.022) on CVFD in the fine wool. These results suggest that variation in KRTAP8-1 affects fibre uniformity in Tan sheep.