The consequences of hybridization are varied, ranging from the origin of new lineages, introgression of some genes between species, to the extinction of one of the hybridizing species. We generated replicate admixed populations between two pairs of sister species of Drosophila: D. simulans and D. mauritiana; and D. yakuba and D. santomea Each pair consisted of a continental species and an island endemic. The admixed populations were maintained by random mating in discrete generations for over 20 generations. We assessed morphological, behavioral, and fitness-related traits from each replicate population periodically, and sequenced genomic DNA from the populations at generation 20. For both pairs of species, species-specific traits and their genomes regressed to those of the continental species. A few alleles from the island species persisted, but they tended to be proportionally rare among all sites in the genome and were rarely fixed within the populations. This paucity of alleles from the island species was particularly pronounced on the X-chromosome. These results indicate that nearly all foreign genes were quickly eliminated after hybridization and that selection against the minor species genome might be similar across experimental replicates.

中文翻译：

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两个果蝇物种对之间混合种群的快速且可预测的进化。


杂交的后果是多种多样的，从新谱系的起源、物种之间某些基因的渗入，到杂交物种之一的灭绝。我们在果蝇的两对姐妹物种之间生成了复制的混合种群： D. simulans和D. mauritiana ； D. yakuba和D. santomea每对都由一个大陆物种和一个岛屿特有物种组成。混合种群通过离散世代的随机交配维持了20多代。我们定期评估每个复制种群的形态、行为和适应性相关特征，并对第 20 代种群的基因组 DNA 进行测序。对于这两对物种，物种特异性特征及其基因组回归到大陆物种的特征。来自岛屿物种的一些等位基因持续存在，但它们在基因组的所有位点中往往相当罕见，并且很少在种群内固定。岛屿物种等位基因的缺乏在X染色体上尤其明显。这些结果表明，杂交后几乎所有外源基因都被迅速消除，并且针对次要物种基因组的选择在实验重复中可能是相似的。