Single nucleotide polymorphisms in four functionally related immune response genes in the horse: CD14,TLR4, Cepsilon, andFcepsilon R1 alpha.

This research examined the variability in four immune response genes in horses and developed methods for identifying these variations. These findings may be useful in studying genetic contributions to infectious and allergic diseases in horses.

Objective and Methodology

• The purpose of the study was to identify single nucleotide polymorphisms (SNPs), or variations in individual components of DNA, in four immune response genes in horses.
• The researchers developed methods to genotype these SNPs, which could aid future genomic studies of horse diseases.
• The four genes under investigation were CD14, TLR4, Cepsilon and FcepsilonR1 alpha. These are all connected with the horse’s immune response.
• To identify SNPs, the research team used horse-specific primers (short strands of DNA that match the target DNA sequence) to make copies of chosen regions within these genes.
• The team then searched for SNPs in these copies using selective resequencing and variations of the PCR (polymerase chain reaction) method, namely PCR-SSCP and PCR-RFLP.

Findings and Conclusions

• The researchers found SNPs in each of the four immune response genes. In total, there were three SNPs in the CD14 gene, four in the TLR4 gene, two in the Cepsilon gene, and one in the FcepsilonR1 alpha gene.
• PCR-RFLP, one of the methods of DNA analysis used by the researchers, was used to genotype eight of these SNPs.
• All identified SNPs exist in parts of genes that are expressed, as shown by reverse transcriptase-PCR, another type of DNA analysis.
• This means the genes with these SNPs do produce proteins, and therefore these SNPs could potentially impact the function of these proteins and the immune response of the horse.
• The researchers concluded that these immune response genes in horses are polymorphic, or variable, and that even non-synonymous SNPs (ones which cause a change in the coded protein) with potential functional effects may occur.
• The methods developed for genotyping and identifying SNP combinations (haplotyping) form a potentially useful tool along with other markers for future genomic analysis of how these genes contribute to immunity and disease in horses.