THE GENETIC ARCHITECTURE OF REPRODUCTIVE ISOLATION DURING SPECIATION-WITH-GENE-FLOW IN LAKE WHITEFISH SPECIES PAIRS ASSESSED BY RAD SEQUENCING
THE GENETIC ARCHITECTURE OF REPRODUCTIVE ISOLATION DURING SPECIATION-WITH-GENE-FLOW IN LAKE WHITEFISH SPECIES PAIRS ASSESSED BY RAD SEQUENCING
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DOI：
10.1111/evo.12075
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发表时间：
2013-09-01
期刊：
影响因子：
3.3
通讯作者：
Bernatchez, Louis
中科院分区：
文献类型：
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作者：
Gagnaire, Pierre-Alexandre;Pavey, Scott A.;Bernatchez, Louis
在基因流动的物种形成过程中，有效迁移在基因组中因多种因素而异，包括所选基因座的接近程度、重组率、选择强度和所选基因座的数量。基因组扫描可以提供更好的经验理解的基因组范围内的遗传分化模式，特别是如果方差由于前面提到的因素被分割。在北美洲的白鲑（Coregonus clupeaformis）中，约60，000年前在异域中分歧并在12，000年前接触的冰川谱系在几个湖泊中独立地进化成两个同域物种对（正常底栖动物和矮湖沼动物）。不同程度的繁殖隔离物种对跨越湖泊提供了一个连续的遗传和表型的分歧与适应不同的生态位。为了解开复杂的阵列，以遗传为基础的障碍，本地减少白鱼物种对之间的有效迁移率，我们比较了基因组范围内的模式，分布在五个湖泊之间的分歧沿着这个分歧连续。使用限制性位点相关DNA（RAD）测序，我们结合了遗传作图和群体遗传学方法，以确定基因组区域耐基因渗入，并获得经验措施的屏障强度作为重组距离的函数。我们发现，基因组岛屿的大小分化的连锁不平衡的联合效应的影响，保持选择在许多位点，生态位分歧的强度，以及独特的人口特征，每个湖泊。不同基因组区域的部分平行性可能反映了多基因适应的综合影响，从常设的变化和独立的遗传结构的合子后隔离的变化。这项研究说明了如何整合多个同域物种对的遗传图谱和种群基因组学提供了一个窗口的物种形成与基因流机制。
During speciation-with-gene-flow, effective migration varies across the genome as a function of several factors, including proximity of selected loci, recombination rate, strength of selection, and number of selected loci. Genome scans may provide better empirical understanding of the genome-wide patterns of genetic differentiation, especially if the variance due to the previously mentioned factors is partitioned. In North American lake whitefish (Coregonus clupeaformis), glacial lineages that diverged in allopatry about 60,000 years ago and came into contact 12,000 years ago have independently evolved in several lakes into two sympatric species pairs (a normal benthic and a dwarf limnetic). Variable degrees of reproductive isolation between species pairs across lakes offer a continuum of genetic and phenotypic divergence associated with adaptation to distinct ecological niches. To disentangle the complex array of genetically based barriers that locally reduce the effective migration rate between whitefish species pairs, we compared genome-wide patterns of divergence across five lakes distributed along this divergence continuum. Using restriction site associated DNA (RAD) sequencing, we combined genetic mapping and population genetics approaches to identify genomic regions resistant to introgression and derive empirical measures of the barrier strength as a function of recombination distance. We found that the size of the genomic islands of differentiation was influenced by the joint effects of linkage disequilibrium maintained by selection on many loci, the strength of ecological niche divergence, as well as demographic characteristics unique to each lake. Partial parallelism in divergent genomic regions likely reflected the combined effects of polygenic adaptation from standing variation and independent changes in the genetic architecture of postzygotic isolation. This study illustrates how integrating genetic mapping and population genomics of multiple sympatric species pairs provide a window on the speciation-with-gene-flow mechanism.