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

觅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古代湖泊的辐射过程中进化出了无与伦比的radula（拉舌）形式的多样性。这个关键表型性状的遗传基础是完全未知的。这个项目的目的是通过集中在一个物种，T. sarasinorum，具有两种高度不同的radula形态来鉴定radula形成和形状的候选基因。将使用Next Generation Sequencing （Illumina）对来自两种变体和三个组织的几个个体的转录组进行高覆盖率测序。组织和形态之间基因表达差异的初步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推定的radula形成候选基因的实际参与将通过原位杂交实验进行测试，其解释将由radula形成组织的超解剖数据辅助。鉴定与产生所观察到的斑痣差异有关的基因将是在遗传水平上理解这种适应性辐射的关键过程的关键一步。

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.