Data from: Extreme genetic diversity in asexual grass thrips populations

The continuous generation of genetic variation has been proposed as one of the main factors explaining the maintenance of sexual reproduction in nature. However, populations of asexual individuals may attain high levels of genetic diversity through within-lineage diversification, replicate transitions to asexuality from sexual ancestors and migration. How these mechanisms affect genetic variation in populations of closely related sexual and asexual taxa can therefore provide insights into the role of genetic diversity for the maintenance of sexual reproduction. Here, we evaluate patterns of intra- and interpopulation genetic diversity in sexual and asexual populations of Aptinothrips rufus grass thrips. Asexual A. rufus populations are found throughout the world, whereas sexual populations appear to be confined to few locations in the Mediterranean region. We found that asexual A. rufus populations are characterized by extremely high levels of genetic diversity, both in comparison with their sexual relatives and in comparison with other asexual species. Migration is extensive among asexual populations over large geographic distances, whereas close sexual populations are strongly isolated from each other. The combination of extensive migration with replicate evolution of asexual lineages, and a past demographic expansion in at least one of them, generated high local clone diversities in A. rufus. These high clone diversities in asexual populations may mimic certain benefits conferred by sex via genetic diversity and could help explain the extreme success of asexual A. rufus populations.持续产生的遗传变异（genetic variation）被认为是解释自然界中有性生殖（sexual reproduction）得以维持的核心因素之一。然而，无性个体（asexual individuals）种群可通过谱系内多样化（within-lineage diversification）、从有性祖先多次独立起源无性生殖谱系，以及种群迁移（migration），获得高水平的遗传多样性（genetic diversity）。因此，上述机制如何影响近缘有性与无性类群（taxa）的种群遗传变异模式，能够为探究遗传多样性在维持有性生殖中的作用提供关键见解。本研究对红足蓟马（Aptinothrips rufus grass thrips）的有性与无性种群的种群内（intrapopulation）及种群间（interpopulation）遗传多样性模式进行了评估。无性红足蓟马种群遍布全球，而有性种群似乎仅局限于地中海地区的少数区域。研究发现，相较于其有性近缘类群以及其他无性物种，无性红足蓟马种群的遗传多样性水平极高。无性种群在大范围地理区间内存在频繁的种群迁移，而地理上邻近的有性种群则彼此间隔离程度极高。频繁的种群迁移结合无性谱系（asexual lineages）的多次独立演化，加之至少一个无性谱系曾经历过种群扩张（demographic expansion），共同造就了红足蓟马无性种群极高的克隆多样性（clone diversity）。无性种群中如此之高的克隆多样性，可能会模拟出有性生殖通过遗传多样性所带来的部分益处，或可帮助解释无性红足蓟马种群为何能取得如此极高的种群成功。