Shekhovtsov S V, Derzhinsky Ye A, Golovanova E V
Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia Institute of Biological Problems of the North of the Far-Eastern Branch of the Russian Academy of Sciences, Magadan, Russia.
Vitebsk State University named after P.M. Masherov, Vitebsk, Belarus.
Vavilovskii Zhurnal Genet Selektsii. 2024 Sep;28(5):563-570. doi: 10.18699/vjgb-24-62.
Earthworms are known for their intricate systematics and a diverse range of reproduction modes, including outcrossing, self-fertilization, parthenogenesis, and some other modes, which can occasionally coexist in a single species. Moreover, they exhibit considerable intraspecific karyotype diversity, with ploidy levels varying from di- to decaploid, as well as high genetic variation. In some cases, a single species may exhibit significant morphological variation, contain several races of different ploidy, and harbor multiple genetic lineages that display significant divergence in both nuclear and mitochondrial DNA. However, the relationship between ploidy races and genetic lineages in earthworms remains largely unexplored. To address this question, we conducted a comprehensive review of available data on earthworm genetic diversity and karyotypes. Our analysis revealed that in many cases, a single genetic lineage appears to encompass populations with different ploidy levels, indicating recent polyploidization. On the other hand, some other cases like Octolasion tyrtaeum and Dendrobaena schmidti/D. tellermanica demonstrate pronounced genetic boundaries between ploidy races, implying that they diverged long ago. Certain cases like the Eisenia nordenskioldi complex represent a complex picture with ancient divergence between lineages and both ancient and recent polyploidization. The comparison of phylogenetic and cytological data suggests that some ploidy races have arisen independently multiple times, which supports the early findings by T.S. Vsevolodova-Perel and T.V. Malinina. The key to such a complex picture is probably the plasticity of reproductive modes in earthworms, which encompass diverse modes of sexual and asexual reproduction; also, it has been demonstrated that even high-ploidy forms can retain amphimixis.
蚯蚓以其复杂的分类系统和多样的繁殖方式而闻名，包括异体受精、自体受精、孤雌生殖以及其他一些繁殖方式，这些繁殖方式偶尔会在单一物种中共存。此外，它们表现出相当大的种内核型多样性，倍性水平从二倍体到十倍体不等，并且具有高度的遗传变异。在某些情况下，单一物种可能表现出显著的形态变异，包含几个不同倍性的种群，并且拥有多个在核DNA和线粒体DNA中都显示出显著差异的遗传谱系。然而，蚯蚓中倍性种群与遗传谱系之间的关系在很大程度上仍未得到探索。为了解决这个问题，我们对蚯蚓遗传多样性和核型的现有数据进行了全面综述。我们的分析表明，在许多情况下，单一遗传谱系似乎包含不同倍性水平的种群，这表明近期发生了多倍体化。另一方面，像八毛蚓属（Octolasion tyrtaeum）和枝蚓属（Dendrobaena schmidti/D. tellermanica）的一些其他情况表明，倍性种群之间存在明显的遗传界限，这意味着它们在很久以前就已经分化。像北寒蚓属（Eisenia nordenskioldi）复合体这样的某些情况呈现出一幅复杂的图景，谱系之间存在古老的分化以及古老和近期的多倍体化。系统发育和细胞学数据的比较表明，一些倍性种群已经多次独立出现，这支持了T.S. 弗谢沃洛多娃 - 佩列尔（T.S. Vsevolodova-Perel）和T.V. 马林娜（T.V. Malinina）早期的研究发现。如此复杂图景的关键可能在于蚯蚓繁殖方式的可塑性，其包括多种有性和无性繁殖方式；此外，已经证明即使是高倍性形式也可以保留两性融合。
