In search of the Goldilocks zone for hybrid speciation
In search of the Goldilocks zone for hybrid speciation
复制标题
DOI：
10.1371/journal.pgen.1007613
复制
发表时间：
2018-09-01
期刊：
影响因子：
4.5
通讯作者：
Bank, Claudia
中科院分区：
文献类型：
--
作者：
Blanckaert, Alexandre;Bank, Claudia
杂交作为观察物种形成机制的独特机会和物种形成的潜在引擎，最近获得了相当大的兴趣。后者仍然是一个有争议的话题。最近有人假设，从亲本物种的遗传不相容性的相互排序可能会导致杂交物种形成，当杂交种群保持一个混合组合的父母不相容性，防止进一步的基因交换与两个父母的人口。然而，尚未从理论上研究多个不兼容性的清除/分类过程的细节。我们在这里调查的等位基因频率动态的一个孤立的杂交群体，结果从一个单一的杂交事件。使用两个或四个基因座的模型，我们调查的一个或两个遗传不相容性的Dobzhansky-Muller型（DMIs）的命运。我们研究了各种参数如何影响排序/清除的DMIs和观察杂交物种形成的概率由相互排序。我们发现，杂交物种形成的概率是强烈依赖于连锁结构（即顺序和重组率之间的基因座沿着染色体），混合人口的人口规模，和最初的相对贡献的亲本人口的混合人口。我们确定了一个适居带特定的连锁结构和中间重组率，在杂交物种形成成为极有可能。而父母的人口的混合人口的平等贡献最大化的混合物种形成的概率在金发区，其他连锁结构产生不直观的不对称的最大值。我们提供了一个解释这种模式，并讨论我们的研究结果都与观察杂交物种形成的最佳条件，在自然界和它们的影响，在杂交区的渗入模式。
Hybridization has recently gained considerable interest both as a unique opportunity for observing speciation mechanisms and as a potential engine for speciation. The latter remains a controversial topic. It was recently hypothesized that the reciprocal sorting of genetic incompatibilities from parental species could result in hybrid speciation, when the hybrid population maintains a mixed combination of the parental incompatibilities that prevents further gene exchange with both parental populations. However, the specifics of the purging/sorting process of multiple incompatibilities have not been examined theoretically. We here investigate the allele-frequency dynamics of an isolated hybrid population that results from a single hybridization event. Using models of two or four loci, we investigate the fate of one or two genetic incompatibilities of the Dobzhansky-Muller type (DMIs). We study how various parameters affect both the sorting/purging of the DMIs and the probability of observing hybrid speciation by reciprocal sorting. We find that the probability of hybrid speciation is strongly dependent on the linkage architecture (i.e. the order and recombination rate between loci along chromosomes), the population size of the hybrid population, and the initial relative contributions of the parental populations to the hybrid population. We identify a Goldilocks zone for specific linkage architectures and intermediate recombination rates, in which hybrid speciation becomes highly probable. Whereas an equal contribution of parental populations to the hybrid population maximizes the hybrid speciation probability in the Goldilocks zone, other linkage architectures yield unintuitive asymmetric maxima. We provide an explanation for this pattern, and discuss our results both with respect to the best conditions for observing hybrid speciation in nature and their implications regarding patterns of introgression in hybrid zones.