Baty Sarah M, Araya-Donoso Raúl, Paulsen Avery, Williams Avery, DeNardo Dale F, Kusumi Kenro, Dolby Greer A
School of Life Sciences, Arizona State University, Tempe, AZ, USA.
Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
Mol Ecol Resour. 2025 Mar 25:e14098. doi: 10.1111/1755-0998.14098.
Genomic incompatibilities and differential ecological adaptation are thought to be fundamental mechanisms of speciation. In this study, we generated a chromosome-scale reference genome and annotation for Gopherus morafkai , the Sonoran Desert tortoise, and conducted a detailed analysis of genes under positive selection with its sister species, the Mojave Desert tortoise. They occupy desert habitats with differing seasonal rainfall patterns and have considerable behavioural and reproductive differences, yet maintain a narrow hybrid zone. We find high conservation of synteny with other chelonian species. Results show extensive positive selection (422 candidate genes) relating to eye development and function that may reflect differences in UV exposure, as well as core reproductive isolation mechanisms of sperm-egg recognition, spindle assembly checkpoint and sister chromatid pairing. Together, our results offer strong genomic support and speciation genomic resources for processes shaping reproductive isolation in chelonians.
基因组不相容性和差异生态适应性被认为是物种形成的基本机制。在本研究中，我们为索诺兰沙漠龟莫拉夫凯氏地鼠龟生成了一个染色体水平的参考基因组和注释，并对其姐妹物种莫哈韦沙漠龟进行了正选择基因的详细分析。它们占据着季节性降雨模式不同的沙漠栖息地，在行为和繁殖方面存在相当大的差异，但仍维持着一个狭窄的杂交带。我们发现与其他龟鳖类物种的染色体同线性具有高度保守性。结果显示，与眼睛发育和功能相关的广泛正选择（422个候选基因）可能反映了紫外线暴露的差异，以及精子 - 卵子识别、纺锤体组装检查点和姐妹染色单体配对等核心生殖隔离机制。总之，我们的结果为龟鳖类生殖隔离形成过程提供了强有力的基因组支持和物种形成基因组资源。
