Heterogeneous genome divergence, differential introgression, and the origin and structure of hybrid zones.
Heterogeneous genome divergence, differential introgression, and the origin and structure of hybrid zones.
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DOI：
10.1111/mec.13582
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发表时间：
2016-06
影响因子：
4.9
通讯作者：
Larson EL
中科院分区：
文献类型：
--
作者：
Harrison RG;Larson EL
杂交区已被推广为进化过程的窗口和研究分歧和物种形成的实验室。杂交物种之间的分歧模式现在可以在全基因组范围内进行表征，最近的基因组扫描集中在分歧“岛屿”的存在上。异质性基因组趋异的模式可能反映了二次接触后的差异渐渗，并提供了哪些基因组区域有助于局部适应，杂交不适应和积极主动交配的见解。然而，异质基因组趋异也可以在没有任何基因流动的情况下出现，这是由于基因组中的选择和重组的变化。我们建议，要了解杂交区的起源和动态，这是必不可少的区分基因组区域之间的分歧纯亲本种群和区域，这些种群在杂交区相互作用，显示出有限的基因渗入。后者比前者更能揭示生殖隔离的可能遗传结构。镶嵌混杂带由于其复杂的结构和多接触面，是区分原生过渡带和次生接触带的特别好的对象。在涉及“相同”物种对的独立杂交区或样带之间进行比较也有助于区分基因流动的分歧和二次接触。然而，从复制混合区或复制样带的数据没有显示一致的模式，在少数情况下，模式的渗入是类似的独立样带，但对于许多类群，有明显缺乏一致性，大概是由于在环境背景和/或相互作用的种群的遗传变异的变化。
Hybrid zones have been promoted as windows on the evolutionary process and as laboratories for studying divergence and speciation. Patterns of divergence between hybridizing species can now be characterized on a genome-wide scale, and recent genome scans have focused on the presence of “islands” of divergence. Patterns of heterogeneous genomic divergence may reflect differential introgression following secondary contact and provide insights into which genome regions contribute to local adaptation, hybrid unfitness, and positive assortative mating. However, heterogeneous genome divergence can also arise in the absence of any gene flow, as a result of variation in selection and recombination across the genome. We suggest that to understand hybrid zone origins and dynamics, it is essential to distinguish between genome regions that are divergent between pure parental populations and regions that show restricted introgression where these populations interact in hybrid zones. The latter, more so than the former, reveal the likely genetic architecture of reproductive isolation. Mosaic hybrid zones, because of their complex structure and multiple contacts, are particularly good subjects for distinguishing primary intergradation from secondary contact. Comparisons among independent hybrid zones or transects that involve the “same” species pair can also help to distinguish between divergence with gene flow and secondary contact. However, data from replicate hybrid zones or replicate transects do not reveal consistent patterns; in a few cases, patterns of introgression are similar across independent transects, but for many taxa, there is distinct lack of concordance, presumably due to variation in environmental context and/or variation in the genetics of the interacting populations.