Variation in caprine KRTAP24-1 may

Variation in caprine KRTAP24-1 may affect cashmere traits in different ways. Firstly, a numberof the SNPs that were found were non-synonymous and would result in amino acid changes in theputative KAP24-1 protein. These amino acid changes may affect the protein structure, its property,or its interaction with IFs, and consequently affect fibre traits. There were three non-synonymous SNPs(c.301T/C, c.319G/A, and c.656T/C) when comparing variants A and B for which a difference in MFDwas detected here. Two of these SNPs are worthy of attention. SNP c.301T/C would result in gain orloss of cysteine, whereas SNP c.319G/A would result in gain or loss of glycine. Cysteine is usually thefirst-limiting amino acid for wool or cashmere fibre synthesis [34] and is essential for the formationof disulphide bonds between KAPs and IFs, whereas glycine is a small residue that may make theKAP protein more flexible and thus better able to form a compact structure with IFs. It is logical thatthe gain of cysteine and glycine for variant A compared to B may favour KAP24-1 forming a morecompact structure with the IFs, and thus lead to a finer fibre, this being consistent with the associationresults. However, as described below, these SNPs may simply be linked to other genetic variation thatmight affect the expression of KRTAP24-1.