The genomic landscape at a late stage of stickleback speciation: High genomic divergence interspersed by small localized regions of introgression.

摘要: Speciation is a continuous process and analysis of species pairs at different stages divergence provides insight into how it unfolds. Previous genomic studies on young have revealed peaks heterogeneous differentiation. Yet less known localised differentiation progress to genome-wide during the later speciation in presence persistent gene flow. Spanning continuum, stickleback are ideal for investigating builds up speciation. However, attention has largely focused postglacial pairs, with little knowledge signatures introgression older systems. The Japanese pair, composed Pacific Ocean three-spined (Gasterosteus aculeatus) Japan Sea (G. nipponicus), which co-occur islands, late stage Divergence likely started well before end last glacial period crosses between females males result hybrid male sterility. Here we use coalescent analyses Approximate Bayesian Computation show that two split approximately 0.68-1 million years ago but they continued exchange genes low rate throughout divergence. Population data that, despite flow, high level maintained across majority genome. identified multiple, small regions introgression, occurring mainly areas recombination rate. Our results demonstrate can establish face flow be localized