Department of Biology, Williams College, Williamstown, Massachusetts, United States of America.
PLoS One. 2018 Dec 19;13(12):e0208498. doi: 10.1371/journal.pone.0208498. eCollection 2018.
The genomic architecture of barriers to gene exchange during the speciation process is poorly understood. The genomic islands model suggests that loci associated with barriers to gene exchange prevent introgression of nearby genomic regions via linkage disequilibrium. But few analyses of the actual genomic location of non-introgressing loci in closely related species exist. In a previous study Maroja et al. showed that in the hybridizing field crickets, Gryllus firmus and G. pennsylvanicus, 50 non-introgressing loci are localized on two autosomal regions and the X chromosome, but they were not able to map the loci along the X chromosome because they used a male informative cross. Here, we localize the introgressing and non-introgressing loci on the X chromosome, and reveal that all X-linked non-introgressing loci are restricted to a 50-cM region with 10 of these loci mapped to a single location. We discuss the implications of this finding to speciation.
物种形成过程中基因交换障碍的基因组结构尚不清楚。基因组岛模型表明，与基因交换障碍相关的基因座通过连锁不平衡来阻止附近基因组区域的基因渗入。但是，在密切相关的物种中，很少有关于非渗入基因座实际基因组位置的分析。在之前的一项研究中，Maroja 等人表明，在杂交的蟋蟀 Gryllus firmus 和 G. pennsylvanicus 中，有 50 个非渗入基因座定位于两个常染色体区域和 X 染色体上，但由于他们使用了雄性信息交叉，因此无法沿 X 染色体对这些基因座进行定位。在这里，我们将 X 染色体上的渗入和非渗入基因座定位，并揭示出所有 X 连锁的非渗入基因座都局限于一个 50-cM 的区域，其中 10 个基因座映射到一个单一的位置。我们讨论了这一发现对物种形成的意义。
