History cleans up messes: the impact of time in driving divergence and introgression in a tropical suture zone

Contact zones provide an excellent arena in which to address questions about how genomic divergence evolves during lineage divergence. They allow us to both infer patterns of genomic divergence in allopatric populations isolated from introgression and to characterize patterns of introgression after lineages meet. Thusly motivated, we analyze genome-wide introgression data from four contact zones in three genera of lizards endemic to the Australian Wet Tropics. These contact zones all formed between morphologically cryptic lineage-pairs within morphologically defined species, and the lineage-pairs meeting in the contact zones diverged anywhere from 3.1 to 5.8 million years ago. By characterizing patterns of molecular divergence across an average of 11K genes and fitting geographic clines to an average of 7.5K variants, we characterize how patterns of genomic differentiation and introgression change through time. Across this range of divergences, we find that genome-wide differentiation i...接触带（contact zone）为探究类群分化过程中基因组分化的演化规律提供了绝佳的研究场景。此类研究体系既可以帮助我们推断因基因渐渗（introgression）而隔离的异域种群（allopatric population）的基因组分化模式，也能够刻画类群相遇后的基因渐渗特征。基于上述研究动机，我们对澳大利亚湿热带（Australian Wet Tropics）特有3个蜥蜴属的4个接触带的全基因组渐渗数据开展了分析。这些接触带均形成于形态学定义物种内部的形态隐存类群对之间，且该类群对的分化时间介于310万至580万年前。我们通过对平均11000个基因的分子分化模式进行刻画，并对平均7500个变异位点拟合地理梯度（geographic cline）模型，解析了基因组分化程度与基因渐渗模式随时间的变化规律。在该分化时间跨度范围内，我们发现全基因组分化……