Polymorphism of Keratin - Associated Protein (KAP) 6.1 gene and its association with wool traits of Sandyno and Nilagiri breeds of sheep

摘要

Polymorphic variants of keratin-associated protein (KAP) 6.1 gene with wool traits of Sandyno and Nilagiri breeds of sheep were investigated in this study. Genomic DNA was isolated from blood samples of 125 Sandyno, Nilagiri and Dorset x Nilagiri breeds of sheep along with 76 numbers of wool samples. A 528 bp segment was amplified by PCR using ovine specific primers for KAP 6.1 gene. SSCP analysis of KAP 6.1 gene in Dorset x Nilagiri crossbred sheep resulted in two genotypes for the A/B with no polymorphism. KAP 6.1 gene locus revealed allele frequencies of A, B, C, D and E in Sandyno sheep were 0.67, 0.23, 0.04, 0.01 and 0.04 and in Nilagiri were 0.75, 0.06, 0.11, 0.04 and 0.04 respectively. KAP 6.1 gene revealed departure from Hardy-Weinberg equilibrium. KAP 6.1 genes were found to have high degree of homozygosity (0.6667) in Nilagiri sheep. The effective number of alleles (N-e) for KAP 6.1 gene was 1.1690 and 1.7006 respectively in Sandyno and Nilagiri breeds of sheep. The PIC values for KAP 6.1 gene was 0.1341 and 0.3909 in Sandyno and Nilagiri breeds of sheep respectively. F-IS values for KAP 6.1 gene was positive (0.1909) in Nilagiri breed and it was negative (-0.0110) in Sandyno breed. Least squares analysis of variance showed significant (P<0.05) effect between genotypes and between sexes for wool traits like GFW (kg), CWY (%) and FD (mu). Significant (P<0.05) effect of breed (Sandyno and Nilagiri) was observed for all the wool traits (GFW, CWY, FD, SL and Medullation %). Significant (p<0.05) higher CWY production was recorded for AC genotype (62.00 +/- 1.73 %) while low value was recorded for BB genotype (56.25 +/- 1.74 %). FD was found to be high in genotype AC (24.29 +/- 1.17 mu) than in AA genotype (23.24 +/- 0.49 mu). The homozygote AA was found to have more Medullation (%) and SL. Genotypes BB had higher GFW and lower CWY. The heterozygous genotype AC yielded more FD and CWY with lower most Medullation (%) and SL values. From the study, it may be concluded that KAP 6.1 gene might be a potential molecular marker for genetic selection of wool traits in Sandyno and Nilagiri breeds of sheep.