Evolutionary Response Patterns of the Rodent TLR Genes to Climatic Factors.

Toll-like receptors (TLRs) are evolutionarily conserved pattern recognition receptors that play a crucial role in the innate immune response of animals. Their evolutionary dynamics are closely linked to pathogen pressure and environmental factors. At present, the relationship between the evolution of TLR genes and climatic factors remains poorly understood. In this study, we identified TLR1-TLR9 genes from 42 rodent species with relatively restricted distribution ranges. Phylogenetic comparative analyses, including phyANOVA and PGLS, were conducted to assess the relationship between evolutionary rates (ω values) and 10 climatic factors. The results indicated that different TLR genes exhibit distinct climate-associated patterns. Notably, increased precipitation-related factors were positively associated with the evolutionary rates of TLR2 and TLR4, whereas temperature-related factors (Mean Diurnal Range) were positively correlated with the evolutionary rates of TLR8 and TLR9. We hypothesized that both precipitation- and temperature-related factors may indirectly influence the evolution of TLR genes by affecting the diversity and community composition of environmental pathogens. These results may enhance our understanding of the evolution of immune genes in animals through the perspective of potential ecological associations.