Slovenian Veterinary Research, cilt.57, sa.1, ss.25-31, 2020 (SCI-Expanded)
Toll-like receptors play an essential role in how the innate immune system reacts to pathogens. These receptors help
the innate immune system recognise the antigenic structure of pathogens and initiate the inflammatory response. TLR4 is one of
these receptors, and it has been identified as a candidate molecular marker for resistance to mastitis in cattle. This study aimed
to describe G-1539A (BgII) in promoter and G+265C (MspI) in 5’-UTR polymorphisms in the TLR4 gene using Zavot (n=60), East
Anatolian Red (EAR, n=49), Anatolian Black (AB, n=59), South Anatolian Red (SAR, n=42), Turkish Gray (TG, n=60) and Holstein
(n=218) cattle breeds. For this purpose, we used polymerase chain reaction and restriction fragment length polymorphism
(PCR-RFLP) to genotype a total of 488 cattle. Two alleles (A and G) and three genotypes (GG, GA and AA) were examined by
digestion of the PCR product with BgII restriction enzyme. The frequency of the G allele was higher in all investigated breeds
except Zavot. The GA genotype was found to be the most common genotype in the EAR, SAR, TG, AB, Holstein, and Zavot
breeds. Two alleles (C and G) and three genotypes (GG, GC and CC) were examined by digestion of the PCR product for the
G+265C SNP with the MspI restriction enzyme. The most prevalent in terms of frequency was the C allele in all breeds with regard
to G+265C SNP. All examined breeds were within the Hardy-Weinberg equilibrium (p>0.05). Consequently, the existence of two
SNPs of the TLR4 gene has been reported for the first time in six cattle breeds raised in Turkey. The study demonstrated that the
investigated breeds continue to exhibit variation in terms of these two SNPs. It might be possible to utilise these polymorphisms
in efforts to breed herds resistant to significant breeding diseases, such as mastitis.