Open AccessContrasting patterns of polymorphism and selection in bacterial‐sensing toll‐like receptor 4 in two house mouse subspecies
Author(s) -
Fornuskova Alena,
Bryja Josef,
Vinkler Michal,
Macholán Miloš,
Piálek Jaroslav
Publication year - 2014
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.1137
Subject(s) - biology , subspecies , genetics , evolutionary biology , haplotype , balancing selection , polymorphism (computer science) , natural selection , gene , genetic variation , zoology , selection (genetic algorithm) , allele , artificial intelligence , computer science
Abstract 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 ( TLR s) belong presently among the best‐studied receptors of vertebrate immunity. TLR s 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 ( Tlr4 ) over the Palearctic range of house mouse ( M us musculus ). Our results reveal contrasting evolutionary patterns between the two recently (0.5 million years ago) diverged house mouse subspecies: M . m. domesticus ( M md) and M . m. musculus ( M mm). Comparison with cytochrome b indicates strong directional selection in M md Tlr4 . Throughout the whole M md western Palaearctic region, a single variant of the ligand‐binding region is spread, encoded mainly by one dominant haplotype (71% of M md). In contrast, Tlr4 in M mm is much more polymorphic with several haplotypes at intermediate frequencies. Moreover, we also found clear signals of recombination between two principal haplogroups in M mm, and we identified eight sites under positive selection in our dataset. Our results suggest that observed differences in Tlr4 diversity may be attributed to contrasting parasite‐mediated selection acting in the two subspecies.