Data from: Speciation over the edge: gene flow among non-human primate species across a formidable biogeographic barrier

Many genera of terrestrial vertebrates diversified exclusively on one or the other side of Wallace’s Line, which lies between Borneo and Sulawesi islands in Southeast Asia, and demarcates one of the sharpest biogeographic transition zones in the world. Macaque monkeys are unusual among vertebrate genera in that they are distributed on both sides of Wallace‘s Line, raising the question of whether dispersal across this barrier was an evolutionary one-off or a more protracted exchange—and if the latter, what were the genomic consequences. To explore the nature of speciation over the edge of this biogeographic divide, we used genomic data to test for evidence of gene flow between macaque species across Wallace’s Line after macaques colonized Sulawesi. We recovered evidence of post-colonization gene flow, most prominently on the X chromosome. These results are consistent with the proposal that gene flow is a pervasive component of speciation—even when barriers to gene flow seem almost insurmountable.

诸多陆生脊椎动物类群仅在东南亚婆罗洲与苏拉威西岛之间的华莱士线（Wallace's Line）两侧的其中一侧完成分化繁衍，而该线正是全球最显著的生物地理过渡带之一。猕猴属在脊椎动物类群中颇为特殊，因其分布范围横跨华莱士线两侧，这引发了一个关键科学问题：跨越这一生物地理屏障的扩散事件，究竟是单次的演化偶然，还是更为持久的跨区交流？若为后者，其对应的基因组学后果又是什么？为探究该生物地理分界边缘的物种形成本质，本研究借助基因组数据，检验了猕猴属物种在定殖苏拉威西岛后，跨华莱士线是否存在基因流。本研究成功检出殖民后基因流的相关证据，且该信号在X染色体上表现最为显著。上述结果佐证了“基因流是物种形成过程中普遍存在的组成部分”这一假说，即便此时的基因流屏障看似几乎无法逾越。