Polymorphisms of chicken TLR3 and 7 in different breeds.

Toll-like receptors (TLRs) mediate immune responses via the recognition of pathogen-associated molecular patterns (PAMPs), thus playing important roles in host defense. Among the chicken (Ch) TLR family, ChTLR3 and 7 have been shown to recognize viral RNA. In our earlier studies, we have reported polymorphisms of TLR1, 2, 4, 5, 15 and 21. In the present study, we amplified TLR3 and 7 genes from different chicken breeds and analyzed their sequences. We identified 7 amino acid polymorphism sites in ChTLR3 with 6 outer part sites and 1 inner part site, and 4 amino acid polymorphism sites in ChTLR7 with 3 outer part sites and 1 inner part site. These results demonstrate that ChTLR genes are polymorphic among different chicken breeds, suggesting a varied resistance across numerous chicken breeds. This information might help improve chicken health by breeding and vaccination.