New paper: Colour genes under selection in colourful salamanders


Burgon, J.D., Vieites, D.R., Jacobs, A., Weidt, S.K., Gunter, H.M., Steinfartz, S., Burgess, K., Mable, B.K. and Elmer, K.R., 2020. Functional colour genes and signals of selection in colour polymorphic salamanders. Molecular Ecology. in press online early

Led by PhD student James Burgon, this paper is a favourite! a project started with colleagues in Scotland, Germany and Spain, coming from plans that were long in the pipeline. A new set of colour candidate genes for amphibians.

Abstract
Colouration has been associated with multiple biologically relevant traits that drive adaptation and diversification in many taxa. However, despite the great diversity of colour patterns present in amphibians the underlying molecular basis is largely unknown. Here, we leverage insight from a highly colour‐variable lineage of the European fire salamander (Salamandra salamandra bernardezi) to identify functional associations with striking variation in colour morph and pattern. The three focal colour morphs—ancestral black‐yellow striped, fully yellow, and fully brown—differed in pattern, visible colouration, and cellular composition. From population genomic analyses of up to 4,702 loci, we found no correlations of neutral population genetic structure with colour morph. However we identified 21 loci with genotype‐phenotype associations, several of which relate to known colour genes. Further, we inferred response to selection at up to 142 loci between the colour morphs, again including several that relate to colouration genes. By transcriptomic analysis across all different combinations, we found 196 differentially expressed genes between yellow, brown, and black skin, 63 of which are candidate genes involved in animal colouration. The concordance across different statistical approaches and ‘omic datasets provide several lines of evidence for loci linked to functional differences between colour morphs, including TYR, CAMK1, and PMEL. We found little association between colour morph and the metabolomic profile of its toxic compounds from the skin secretions. Our research suggests that current ecological and evolutionary hypotheses for the origins and maintenance of these striking colour morphs may need to be revisited.


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