Data from: Purifying selection in the toll-like receptors of song sparrows Melospiza melodia

We examined seven TLR genes in song sparrows (Melospiza melodia), a species that is studied across North America. We then examined sequences from four unduplicated TLRs (TLR1LB, TLR3, TLR4 and TLR15) from birds in two parts of the species’ range (N = 27, N = 6), tested for evidence of selection, and conducted pilot analyses of the role of TLR heterozygosity in survival. We identified 45 SNPs: 19 caused changes in amino acid sequences, and two of these were likely deleterious.

We found no evidence of codon-level episodic positive selection, but detected purifying selection at codons in all TLRs. Contrary to expectations we found no strong correlation between heterozygosity at TLRs and inbreeding coefficient f (estimate ± se = -0.68 ± 0.37, Radj2 = 0.08, F1,25 = 3.38, p = 0.08). In addition, pilot analyses revealed no relationship between TLR heterozygosity and survival (β ± SE: 0.09 ± 2.00, p = 0.96), possibly due to small sample size.

Further analyses of genetic diversity in TLRs are likely to advance understanding of the effects of innate immune gene diversity on the fitness and persistence of wild populations. Usage notes data for dryad This data was used to investigate the effects of TLR heterozygosity on survival of song sparrows from Mandarte Island BC, Canada,