The genetic basis of a morphological key trait: radula genes and the adaptive radiation of the freshwater snail Tylomelania

摄食器官的特化在许多适应性辐射中起着至关重要的作用。淡水腹足动物Tylomelania也是如此，它在印度尼西亚苏拉威西岛的古老湖泊中辐射过程中进化出了无与伦比的齿舌（锉舌）形式多样性。这种关键表型性状的遗传基础是完全未知的。本项目的目的是通过对一个物种T. sarasinorum，具有两个高度不同的齿舌变体。将使用下一代测序（Illumina）对来自两种变体和三种组织的几个个体的转录组进行测序，其中每一个具有高覆盖率。组织和形态之间基因表达差异的主要分析将通过观察基因功能和SNP差异来补充。从转录组数据中确定的齿舌形成的推定候选基因的实际参与将通过原位杂交实验进行测试，其解释将通过齿舌形成组织的超解剖学数据进行辅助。鉴定参与创造的齿舌差异观察到的Tylomelania基因将是一个关键的一步，了解这种适应性辐射的关键过程在遗传水平上。

Specializations of the feeding organs play a crucial role in many adaptive radiations. This is also true for the freshwater gastropod Tylomelania, which has evolved an unparalled diversity of radula (rasping tongue) forms in the course of its radiation in ancient lakes on the Indonesian island Sulawesi. The genetic basis of this key phenotypic trait is entirely unknown. The aim of this project is the identification of candidate genes for radula formation and shape by focussing on one species, T. sarasinorum, with two highly distinct radula morphs. Transcriptomes of several individuals from both morphs and three tissues each will be sequenced with a high coverage using Next Generation Sequencing (Illumina). The primary analysis of gene expression differences between tissues and morphs will be complemented by looking at gene function and SNP differences. The actual involvement of the putative candidate genes for radula formation identified from the transcriptome data will be tested by in situ hybridization experiments, whose interpretation will be aided by data on the ultra-anatomy of the radula forming tissue. The identification of genes involved in creating the radula differences observed Tylomelania will be a crucial step towards understanding key processes of this adaptive radiation at the genetic level.