Contrasting patterns of polymorphism and selection in bacterial‐sensing toll‐like receptor 4 in two house mouse subspecies. Issue 14 (20th June 2014)

• Record Type: Journal Article
• Authors: Fornuskova, Alena; Bryja, Josef; Vinkler, Michal; Macholán, Miloš; Piálek, Jaroslav
• Is Part Of: Ecology and evolution. Volume 4:Issue 14(2014)
• Page Start: 2931
• Page End: 2944
• Publication Date: 2014-06-20
• Subjects: Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.1137
• Languages: English
• ISSNs: 2045-7758

Abstract

<abstract abstract-type="main" id="ece31137-abs-0001"> <title>Abstract</title> <p>Detailed investigation of variation in genes involved in pathogen recognition is crucial for understanding co‐evolutionary processes between parasites and their hosts. Triggering immediate innate response to invading microbes, Toll‐like receptors (TLRs) belong presently among the best‐studied receptors of vertebrate immunity. TLRs exhibit remarkable interspecific variation and also intraspecific polymorphism is well documented. In humans and laboratory mice, several studies have recently shown that single amino acid substitution may significantly alter receptor function. Unfortunately, data concerning polymorphism in free‐living species are still surprisingly scarce. In this study, we analyzed the polymorphism of Toll‐like receptor 4 (<italic>Tlr4</italic>) over the Palearctic range of house mouse (<italic>Mus musculus</italic>). Our results reveal contrasting evolutionary patterns between the two recently (0.5 million years ago) diverged house mouse subspecies: <italic>M. m. domesticus</italic> (Mmd) and <italic>M. m. musculus</italic> (Mmm). Comparison with cytochrome <italic>b</italic> indicates strong directional selection in Mmd <italic>Tlr4</italic>. Throughout the whole Mmd western Palaearctic region, a single variant of the ligand‐binding region is spread, encoded mainly by one dominant haplotype (71% of Mmd). In contrast, <italic>Tlr4</italic> in Mmm is much more polymorphic with several haplotypes at intermediate frequencies. Moreover, we also found clear signals of recombination between two principal haplogroups in Mmm, and we identified eight sites under positive selection in our dataset. Our results suggest that observed differences in <italic>Tlr4</italic> diversity may be attributed to contrasting parasite‐mediated selection acting in the two subspecies.</p> </abstract>