Single-nucleotide polymorphism-based genetic diversity analysis of the Kilakarsal and Vembur sheep breeds

The present study was thus undertaken to analyze the genetic diversity of Kilakarsal and Vembur sheep breeds using single-nucleotide polymorphism (SNP) markers within Toll-like receptor (TLR) 3, 5, 6, 9, and 10 genes. Competitive allele-specific polymerase chain reaction (PCR)-based end-point genotyping was performed using real-time PCR to type the SNPs. Allele discrimination module implemented in real-time PCR was utilized to call the genotypes based on fluorescence intensity recorded for each of the two alleles. Basic diversity indices, namely, gene frequencies, observed heterozygosity, expected heterozygosity, and inbreeding coefficient (F ), and testing for Hardy-Weinberg equilibrium (HWE) were estimated using package for elementary analysis of SNP data software program. Of the 25 SNPs, 22 were found to be polymorphic, whereas two SNPs, namely, TLR3_1081_AC and TLR9_2036_CT, were monomorphic in both Kilakarsal and Vembur sheep populations. The SNP TLR10_1180_AG was monomorphic in Kilakarsal but polymorphic in Vembur sheep. The observed heterozygosities were estimated as 0.289 and 0.309 in Kilakarsal and Vembur sheep, respectively, whereas the expected heterozygosity values were 0.305 and 0.309 in the two breeds, respectively. The overall mean F was 0.107 ranging from -0.005 to 0.241 in Kilakarsal sheep and -0.047 ranging from -0.005 to 0.255 in Vembur sheep. In Kilakarsal sheep, the test for HWE revealed TLR9_1308_GC SNP locus with significant deviation (p