Genetic variation in the ovine KAP22-1 gene and its effect on wool traits in Egyptian sheep

The objective of this study was to investigate the genetic polymorphisms in the keratin-associated protein (KAP22-1) gene in Barki ([Formula: see text]), Rahmani ([Formula: see text]) and Ossimi ([Formula: see text]) as the three major sheep breeds in Egypt. Subsequently, the detected variants were correlated with important wool traits. The traits included greasy fleece weight (GFW, g), staple length (SL, cm), prickle factor (PF, %), medullated fiber (MF, %), fiber diameter (FD, [Formula: see text] m), crimp percentage (CR, %) and the standard deviation of FD (SD [Formula: see text] , [Formula: see text] m), as well as the subjectively assessed traits of kemp score (KS), handle grade (HG), greasy color grade (GCG), bulk grade (BG), luster grade (LG) and staple structure (SST). Animals were genotyped by polymerase chain reaction (PCR) – single strand conformation polymorphism (SSCP). Five SSCP banding patterns representing three different nucleotide variants (A, B and C) were detected. DNA sequencing confirmed three single nucleotide polymorphisms (SNPs). Animal age significantly affected GFW ([Formula: see text]), SD [Formula: see text] ([Formula: see text]), SL ([Formula: see text]), CR ([Formula: see text]), KS ([Formula: see text]), LG ([Formula: see text]) and SST ([Formula: see text]). Likewise, the breed had a significant effect on all studied traits except HG and BG, which was not significant. Results showed significant associations between the KAP22-1 variants and CR ([Formula: see text]), SL ([Formula: see text]), KS ([Formula: see text]) and GCG ([Formula: see text]). Interestingly, animals with BB genotypes tended to produce more wool yield ([Formula: see text] g) with high SL ([Formula: see text] cm), CR ([Formula: see text] %) and KS ([Formula: see text]). Results of this study strongly recommend the KAP22-1 gene as a candidate gene for wool production traits in Egyptian sheep, with new useful insights into the visually assessed wool traits. The identified genetic markers may be incorporated into breeding strategies and genetic improvement programs of wool traits in Egyptian sheep.