Sulawesi's divergent tarsiers: The who, Why and How of gene flow in a secondary contact zone

苏拉威西岛的微板块构造历史使岛上的许多特有动物出现了显著的多样化。但是，当密切相关的异域类群发生二次接触时会发生什么呢？最近对神秘的灵长类动物塔西乌斯属的研究提供了证据，证明了异父物种之间的强烈偏斜渐渗杂交。严格的单向mtDNA渗入与滇氏眼镜猴和拉良眼镜猴之间缺乏Y-DNA交换形成对比。本研究旨在揭示这种不对称基因流动的基本原理，特别是确定交配前或合子后的分离机制。眼镜猴是否主动分散到异种范围内，或者观察到的模式是植根于边界的杂交和随后的基因渗入？在一个没有外来传播障碍的杂交区，将捕获60只眼镜猴，其中32只——大多数是预分散的亚成虫——将在6个月的时间里通过无线电跟踪来追踪跨界迁徙。将进行回放试验，以测试二重唱歌曲对配偶识别的重要性，从而在混合区寻找潜在增强的接收器选择性的痕迹。眼镜猴在常染色体、y染色体和线粒体上的基因分型将进一步阐明生殖隔离的遗传学。

Sulawesi’s microplate tectonic history gave rise to a remarkable diversification of many of the island’s endemic animals. But what happens when closely related allopatric taxa come into secondary contact? Recent research on the enigmatic primate genus Tarsius provided evidence of strongly skewed introgressive hybridisation between parapatric species. Strictly unidirectional mtDNA introgression contrasts with a lack of Y-DNA exchange between Dian’s and Lariang tarsiers. This study is set to reveal the rationale for this asymmetric gene flow, especially to identify premating or postzygotic isolating mechanisms. Do tarsiers actively disperse into heterospecific ranges or is the observed pattern rooted in hybridisation at the boundary and subsequent gene introgression? In a hybrid zone with no extrinsic barrier to dispersal, 60 tarsiers will be captured and 32 of these – mostly predispersing subadults – will be radio-tracked over the course of six months to trace cross-boundary migration. Playback trials will be conducted to test the significance of duet songs for mate recognition thereby seeking traces of potentially reinforced receiver selectivity in the hybrid zone. Genotyping tarsiers at various autosomal, Y-chromosomal and mitochondrial loci will shed further light on the genetics of reproductive isolation.