The benefits of interpopulation hybridization diminish with increasing divergence of small populations

Interpopulation hybridization can increase the viability of small populations suffering from inbreeding and genetic drift, but it can also result in outbreeding depression. The outcome of hybridization can depend on various factors, including the level of genetic divergence between the populations, and the number of source populations. Furthermore, the effects of hybridization can change between generations following the hybridization. We studied the effects of population divergence (low vs. high level of divergence) and the number of source populations (two vs. four source populations) on the viability of hybrid populations using experimental Drosophila littoralis populations. Population viability was measured for seven generations after hybridization as proportion of populations facing extinction and as per capita offspring production. Hybrid populations established at the low level of population divergence were more viable than the inbred source populations and had higher offspring p...

种群间杂交（interpopulation hybridization）可提升受近交（inbreeding）与遗传漂变（genetic drift）胁迫的小型种群的生存能力，但也可能引发远交衰退（outbreeding depression）。杂交的结局受多种因素影响，包括种群间的遗传分化（genetic divergence）水平以及源种群（source population）的数量。此外，杂交的效应可在杂交后的不同世代间发生动态变化。本研究以实验构建的海滨果蝇（Drosophila littoralis）种群为材料，探究了种群分化水平（低分化vs.高分化）与源种群数量（2个vs.4个源种群）对杂交种群生存能力的影响。本研究在杂交后的7个世代中，以面临灭绝的种群占比与单只个体的后代产出量作为种群生存能力的衡量指标。遗传分化水平较低的杂交种群相较于近交源种群具有更高的生存能力，且后代产出量更高……