Abstract
Variation in KRTAP6-1 has been reported to affect wool fibre traits in Merino cross-breed sheep and Chinese Tan sheep, but little is known about whether these effects persist in other breeds. In this study, variation in KRTAP6-1 was investigated in 290 New Zealand (NZ) Romney ewes sired by 16 different rams. Polymerase chain reaction single-stranded conformational polymorphism (PCR-SSCP) analysis revealed four variants (, , and of KRTAP6-1, and nine genotypes (AA, AB, AE, AF, BB, BE, BF, EE and FF) in these ewes. Among the 243 ewes that had genotypes with a frequency of over 5 % (i.e. AA, AB and BB), the presence of was found to be associated with reduced mean fibre diameter (MFD) and increased coefficient of variation in fibre diameter (CVFD), whereas the presence of had a trend of association with decreased coarse edge measurement (CEM). A genotype effect was also detected for MFD and CVFD. No associations were detected for fibre diameter standard deviation (FDSD), mean fibre curvature (MFC) and medulation. These results suggest that variation in KRTAP6-1 affects wool fibre diameter in NZ Romney ewes, confirming the finding in Merino cross-breed sheep.
Highlights
Keratin-associated proteins and keratin intermediate filament proteins are the major structural proteins of wool, and they cross-link to form the skeleton of wool fibres (Powell and Rogers, 1997)
Five variant sequences have been identified at the KRTAP6-1 locus and this variation has been reported to be associated with various mean fibre diameter (MFD)-associated traits in Merino cross-breed sheep (Zhou et al, 2015), and fibre length and crimping in early life in Chinese Tan sheep (Tao et al, 2017)
The detection of variant F resulted in the definition of three new single-nucleotide polymorphisms (SNPs) at c.∗4, c.∗10 and c.∗34, and these SNPs were in linkage (Fig. 1b)
Summary
Keratin-associated proteins and keratin intermediate filament proteins are the major structural proteins of wool, and they cross-link to form the skeleton of wool fibres (Powell and Rogers, 1997). The HGT-KAPs are the first group of KAPs to be produced in active wool follicles, and soon after the synthesis of the keratins (Rogers, 2006) They vary considerably in abundance between and within sheep breeds (Gillespie, 1990). Five variant sequences have been identified at the KRTAP6-1 locus and this variation has been reported to be associated with various mean fibre diameter (MFD)-associated traits in Merino cross-breed sheep (Zhou et al, 2015), and fibre length and crimping in early life in Chinese Tan sheep (Tao et al, 2017) These findings suggest variation in KRTAP6-1 affects wool traits, but little is known
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