Genotypic Variations of Toll-Like Receptors 4 Gene and its Association with Intra-Mammary Infections in Rathi Cattles -

Toll-like receptors (TLR) have been identified as crucial molecules for detection of invading pathogens and induction of host defence mechanism through recognition of pathogen-associated specific molecular patterns. Rathi cattle of Rajasthan is known for its disease resistance and milking potential. The present study was conducted to explore the genetic polymorphism in TLR4 gene by PCR-RFLP method and its association with mastitis in Rathi cattle. Blood samples (5 ml) were collected from 58 unrelated Rathi cattle (including 23 were suffered/suffering from mastitis) under aseptic conditions. Genomic DNA was isolated and TLR31 locus (343 bp) of TLR4 gene was amplified by PCR using specific primers. HaeIII restriction enzyme was used for digestion and 343 amplicons produced two different restriction patterns in the mastitic and control population. The first pattern was considered as ‘BB’ genotype having fragment sizes of 49 bp, 98 bp and 196 bp size. The other pattern was considered as ‘AB’ genotype having fragment sizes of 49 bp, 98 bp, 196 bp and 245 bp. The genotypic frequency of mastitic Rathi population was found to be 0.70 and 0.30 for ‘BB’ and ‘AB’ genotypes respectively, whereas the gene frequency of ‘A’ and ‘B’ allele in mastitic animals were found to be 0.15 and 0.85, respectively. Statistical analysis of association of TLR4 variants with mastitis by chi-square test did not revealed any significant difference (P≥0.05) between ‘AB’ and ‘BB’ genotypes in the mastitic.