Poster Presentation Society for Molecular Biology and Evolution Conference 2016

The genetic basis of an adaptive key trait – radula genes in the radiation of Tylomelania (#386)

Leon Hilgers 1 , Michael Hofreiter 2 , Stefanie Hartmann 2 , Thomas von Rintelen 1
  1. Museum für Naturkunde Berlin - Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
  2. Institute of Biochemistry and Biology, Faculty of Mathematics and Natural Sciences, University of Potsdam, Potsdam, Brandenburg, Germany

Specializations of the feeding apparatus play a crucial role in many adaptive radiations. Examples of such adaptive key traits include the beak of Darwin’s finches and pharyngeal as well as oral jaws of the East African cichlids. Despite intensive research on the genomics of adaptation and speciation, our understanding of the genetic basis of these processes and involved phenotypic traits is still in its infancy. Tylomelania is a genus of viviparous freshwater snails endemic to Sulawesi (Indonesia) that comprises riverine and lacustrine clades, the latter of which have undergone radiations in the ancient lakes of the island. In contrast to the riverine species, lacustrine taxa exhibit unparalleled habitat-correlated radula (rasping tongue) diversity. To investigate the genetic basis of this putatively adaptive trait, we generated morph-wise transcriptomes of the mantle and radula-forming tissue of Tylomelania sarasinorum, a species that exhibits a striking substrate-correlated radula polymorphism. Here we present the first radula-forming tissue transcriptome and compare sequence and expression information from both ecomorphs to investigate the genetic basis of radula shape and formation. The assembled transcriptomes give first insights into the genetic basis of radula formation and add to the existing information on molluscan shell biomineralization. Differential expression analysis illuminated tissue specific patterns, and, combined with SNP analyses, generated a list of candidate genes that likely contribute to radula diversity. This study is the first step towards uncovering the genetic basis of radula diversification in Tylomelania which will ultimately add to our understanding of the genetic underpinnings of adaptive traits.