New Paper: genetics of belly colour differences in common lizards

 Just out free and open access in Molecular Ecology, a paper led by Hans and Henrique to test the genetic basis of different ventral colourations and patterns in common lizards. Using samples from the hybrid zone where we have been studying reproductive mode, Henrique studied the gene expression (Honours thesis project) and Hans the GWAS and the colour phenotyping (NERC Postdoc). Now a bunch of new candidate genes that can be followed up for reptiles!


Genetic basis and expression of ventral colour in polymorphic common lizards

Hans Recknagel, Henrique G. Leitão, Kathryn R. Elmer

Abstract

Colour is an important visual cue that can correlate with sex, behaviour, life history or ecological strategies, and has evolved divergently and convergently across animal lineages. Its genetic basis in non-model organisms is rarely known, but such information is vital for determining the drivers and mechanisms of colour evolution. Leveraging genetic admixture in a rare contact zone between oviparous and viviparous common lizards (Zootoca vivipara), we show that females (N = 558) of the two otherwise morphologically indistinguishable reproductive modes differ in their ventral colouration (from pale to vibrant yellow) and intensity of melanic patterning. We find no association between female colouration and reproductive investment, and no evidence for selection on colour. Using a combination of genetic mapping and transcriptomic evidence, we identified two candidate genes associated with ventral colour differentiation, DGAT2 and PMEL. These are genes known to be involved in carotenoid metabolism and melanin synthesis respectively. Ventral melanic spots were associated with two genomic regions, including a SNP close to protein tyrosine phosphatase (PTP) genes. Using genome re-sequencing data, our results show that fixed coding mutations in the candidate genes cannot account for differences in colouration. Taken together, our findings show that the evolution of ventral colouration and its associations across common lizard lineages is variable. A potential genetic mechanism explaining the flexibility of ventral colouration may be that colouration in common lizards, but also across squamates, is predominantly driven by regulatory genetic variation.



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