Evidence of linkage between high‐glycine‐tyrosine keratin gene loci and wool fibre diameter in a Merino half‐sib family

Abstract

SummaryCandidate genes for quantitative trait loci have been studied in a Medium Peppin Merino flock. Obvious candidates for effects on wool production traits are genes for the major proteins expressed in the wool fibre, the keratin and keratin‐associated protein genes. Two keratin‐associated protein loci, KRTAP6 and KRTAP8, have previously been shown to be linked. The results of analyses between these two loci and production traits gave significant evidence of linkage with wool fibre diameter in one out of eight halfsib groups tested. High‐glycine‐tyrosine proteins (KRTAP6, 7 and 8) are known to vary considerably in abundance in wool fibres and it is possible that a gene for major effect on fibre diameter is located within the same chromosomal region as KRTAP6 and KRTAP8.

Merino sheep: a further look at quantitative trait loci for wool production

“…Using different sheep resources (mainly in cross-breeding designs), and different analytical methods (all within the context of linkage analysis and single trait and one-QTL testing) and diverse mapping methods (genome scan or candidate gene approaches), several QTLs have been found using MS markers for wool traits (Purvis and Franklin, 2005;http://sphinx.vet.unimelb.edu.au/QTLdb/) A QTL for FD (Parsons et al, 1994) and for 'objectionable fibre content' (this trait being defined as a large medullated fibres with a latticed medulla deficient in sulphur by Allain et al, 2006) on OAR1 were reported. These authors found a QTL close to the position of the KAP6-KAP8 genes (around 145 cM).…”

Polymorphisms of KAP6, KAP7, and KAP8 genes in four Chinese sheep breeds

“…The amount of protein from different groups varies both spatially and developmentally within the wool fiber (Powell and Rogers, 1990). Specifically, the most significant variation was found with respect to HGTP contents, which varied both within and between species, ranging from less than 3% in human hair and in the wool of Lincoln sheep, to 13% in Merino sheep, and up to 30-40% in echidna quill (Gillespie and Broad, 1972;Parsons et al, 1994).…”

Identification of Polymorphism in the Keratin Genes (KAP3.2, KAP6.1, KAP7, KAP8) and Microsatellite BfMS in Merino Sheep Using Polymerase Chain Reaction-Single Strand Conformational Polymorphism (PCR-SSCP) Analysi

“…The authors did not describe the alleles associated, and no sequence data was presented. Though alleles at the KAP8 microsatellite locus were not sequenced in this study, it is possible that SL2's alleles were different from those associated with differences in average MFD by Parsons et al, (1994a).…”

“…The microsatellite at the KAP8 locus was included in the study because this region is highly polymorphic, with 15 alleles previously reported (Wood et al, 1992) using denaturing polyacrylamide gel electrophoresis, while Parsons et al (1994a) detected four allelic fragments (123, 125, 133 and 139 bp) at the same locus using the methods by Wood et al (1992) in a Merino half-sib family. Only SL2 was heterozygous at the KAP8 microsatellite in this study.…”

“…Numerous studies have described variation within both the KAP and KRT genes, including the work of Rogers et al (1994a); Parsons et al (1994a;1996); McLaren et al (1997); Beh et al (2001); Itenge-Mweza et al (2007). There are some reports associating variation in the KRT and KAP genes with variation in wool traits.…”