Victorian Centre of Aquatic Pollution Identification and Management, Bio21 Institute, The Department of Zoology, The University of Melbourne, Parkville, Victoria 3010, Australia.
Insect Sci. 2013 Jun;20(3):345-57. doi: 10.1111/j.1744-7917.2012.01564.x. Epub 2012 Oct 22.
Parthenogenesis is common among invasive pest species, with many parthenogenetic species also showing polyploidy. Parthenogenetic polyploid species often have multiple hybrid origins and the potential to rapidly spread over vast geographical areas. In this study, we examine patterns of mitochondrial and microsatellite variation in a widespread triploid parthenogenetic chironomid pest species, Paratanytarsus grimmii. Based on samples from five countries, including Australia, England, Germany, Japan, and Canada, we found extremely low mitochondrial diversity (<0.14%), with most individuals sharing a common and widespread haplotype. In contrast, microsatellite diversity revealed 41 clonal variants, which were regionally endemic. These findings suggest a single invasive maternal lineage of P. grimmii is likely to have recently spread over a broad geographical range. High levels of genotypic endemism suggest P. grimmii populations have remained relatively isolated after an initial spread, with little ongoing migration. This, in part, can be attributed to rapid genetic differentiation via mutations of common clonal genotypes after P. grimmii spread, but multiple polyploidization and subsequent founder events are also likely to be contributing factors.
孤雌生殖在入侵性害虫物种中很常见，许多孤雌生殖物种也表现出多倍体现象。 具有孤雌生殖多倍体的物种通常具有多种杂种起源和迅速在广阔地理区域内传播的潜力。 在这项研究中，我们研究了广泛分布的三倍体孤雌生殖摇蚊害虫 Paratanytarsus grimmii 的线粒体和微卫星变异模式。 基于来自五个国家的样本，包括澳大利亚、英国、德国、日本和加拿大，我们发现线粒体多样性极低（<0.14%），大多数个体共享一种常见且广泛分布的单倍型。 相比之下，微卫星多样性揭示了 41 个克隆变体，这些变体在区域内具有地方特色。 这些发现表明，P. grimmii 的单一入侵母系很可能最近在广泛的地理范围内传播。 高基因型特有性表明，P. grimmii 种群在最初传播后一直相对孤立，几乎没有持续的迁移。 这部分归因于 P. grimmii 传播后常见克隆基因型的突变导致的快速遗传分化，但多倍体化和随后的奠基事件也可能是促成因素。
