Abstract
The results of hybrid resequencing of the TLR2 gene using HiSeq and PacBio technologies of pooled population samples of the Czech Simmental (Czech Red) cattle allowed to determine haplotypes within the range of the designed PacBio amplicons. While the frequencies of haplotypes in the amplicons 2 - 5 were randomly distributed, 15 haplotypes in amplicon 1 from the proximal part of the transcript formed two distinct groups.
This phenomenon has been reported earlier in a panel of world breeds and interpreted by alternating infectious agents. However, in a long-time perspective the mechanism sustaining this equilibrium should be more stable and based on two different essential functions performed by the TLR2 gene or its product.
Such a dual function might be formation of two kinds of heterodimers, TLR1/TLR2 and TLR6/TLR2. The localisation of the bimodal group of haplotypes in the non-coding region does not support this assumption, but rather indicates localisation of the selection target in the upstream regulatory region of the gene.
Nevertheless, functional interactions in the proximal part of the transcript cannot be excluded. Individual genotyping of 164 bulls has not brought the answer yet, due to a low density of SNPs genotyped.