Data from: The genomics of incompatibility factors and sex determination in hybridizing species of Cottus (Pisces)

Cottus rhenanus and Cottus perifretum have formed hybrid lineages and narrow hybrid zones that can be best explained through the action of natural selection. However, the underlying selective forces as well as their genomic targets are not well understood. This study identifies genomic regions in the parental species that cause hybrid incompatibilities and tests whether these manifest in a sex-specific manner to learn about processes that affect natural hybridization in Cottus. Interspecific F2 crosses were analyzed for 255 markers for genetic mapping and to detect transmission distortion as a sign for genetic incompatibilities. The Cottus map consists of 24 linkage groups with a total length of 1575.4 cM. A male heterogametic (XY) sex determination region was found on different linkage groups in the two parental species. Genetic incompatibilities were incomplete, varied among individuals and populations and were not associated with the heterogametic sex. The variance between populations and individuals makes it unlikely that there are species-specific incompatibility loci that could affect the gene pool of natural hybrids in a simple and predictable way. Conserved synteny with sequenced fish genomes permits to genetically study the Cottus genome through the transfer of genomic information from the model fish species. Homology relationships of candidate genomic regions in Cottus indicate that sex determination is not based on the same genomic regions found in other fish species. This suggests a fast evolutionary turnover of the genetic basis of sex determination that, together with the small size of the heterogametic regions, may contribute to the absence of fitness effects related to the Haldane’s rule.莱茵杜父鱼（Cottus rhenanus）与珀氏杜父鱼（Cottus perifretum）已形成杂交谱系与狭窄杂交带，该现象最适宜通过自然选择的作用加以解释。然而其潜在的选择压力及其基因组靶点仍未得到充分阐释。本研究鉴定了亲本物种中导致杂交不相容性的基因组区域，并检验这些区域是否以性别特异性方式显现，以解析影响杜父鱼属自然杂交过程的分子机制。本研究对种间F₂杂交后代的255个标记开展遗传作图分析，并通过检测传递偏倚现象作为遗传不相容性的指征。杜父鱼的遗传图谱包含24个连锁群，总长度达1575.4厘摩（cM）。在两个亲本物种的不同连锁群上均发现了雄性异配（XY）性别决定区域。遗传不相容性表现不完全，且存在个体与种群间的差异，并未与异配性别相关联。种群与个体间的差异表明，难以存在以简单可预测方式影响自然杂交种群基因库的物种特异性不相容位点。通过与已测序的鱼类基因组开展保守同线性分析，可借助模式鱼类的基因组信息对杜父鱼属基因组开展遗传学研究。杜父鱼候选基因组区域的同源性分析显示，其性别决定机制并非基于其他鱼类中已发现的同源基因组区域，这表明性别决定的遗传基础存在快速的进化更替；结合异配区域规模较小的特征，这可能解释了为何未观察到与霍尔丹法则（Haldane’s rule）相关的适合度效应。