The evolution of bat nucleic acid-sensing Toll-like receptors

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Publication Date

12-1-2015

Publication Title

Molecular Ecology

Volume Number

24

Issue Number

23

Abstract

We characterized the nucleic acid‐sensing Toll‐like receptors ( TLR ) of a New World bat species, the common vampire bat ( Desmodus rotundus ), and through a comparative molecular evolutionary approach searched for general adaptation patterns among the nucleic acid‐sensing TLR s of eight different bats species belonging to three families ( Pteropodidae, Vespertilionidae and Phyllostomidae ). We found that the bat TLR s are evolving slowly and mostly under purifying selection and that the divergence pattern of such receptors is overall congruent with the species tree, consistent with the evolution of many other mammalian nuclear genes. However, the chiropteran TLR s exhibited unique mutations fixed in ligand‐binding sites, some of which involved nonconservative amino acid changes and/or targets of positive selection. Such changes could potentially modify protein function and ligand‐binding properties, as some changes were predicted to alter nucleic acid binding motifs in TLR 9. Moreover, evidence for episodic diversifying selection acting specifically upon the bat lineage and sublineages was detected. Thus, the long‐term adaptation of chiropterans to a wide variety of environments and ecological niches with different pathogen profiles is likely to have shaped the evolution of the bat TLR s in an order‐specific manner. The observed evolutionary patterns provide evidence for potential functional differences between bat and other mammalian TLR s in terms of resistance to specific pathogens or recognition of nucleic acids in general.

Document Type

Article

Digital Object Identifier (DOI)

https://doi.org/10.1111/mec.13431

Language

English

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