King R Andrew, Tibble Amy L, Symondson William O C
Cardiff School of Biosciences, Biomedical Sciences Building, Cardiff University, Museum Avenue, Cardiff CF10 3US, UK.
Mol Ecol. 2008 Nov;17(21):4684-98. doi: 10.1111/j.1365-294X.2008.03931.x. Epub 2008 Oct 7.
Earthworms play a major role in many aspects of soil fertility, food web ecology and ecosystem functioning, and hence are frequently the subjects of, for example, ecological and toxicological research. Our aim was to examine the genetic structure of common earthworm species, to identify cryptic lineages or species that may be distinct ecotypes or biotypes (and hence confound current research based upon morphotypes) and to try to explain the massive cryptic diversity that eventually emerged. We demonstrated that species such as Allolobophora chlorotica, Aporrectodea longa, Aporrectodea rosea and Lumbricus rubellus all comprise highly divergent lineages with species-level divergence at the mitochondrial cytochrome oxidase I (COI) gene. In Allo. chlorotica alone, we found 55 haplotypes for COI, with 35 of these being found in pink and 20 in green morph worms. There were no cases of the two colour morphs sharing COI haplotypes. Phylogenetic analyses of mitochondrial COI and 16S genes showed the presence of five highly divergent lineages, suggesting the presence of multiple cryptic species within Allo. chlorotica. There was no clear geographical pattern to lineage distribution and many populations were polymorphic for both mitochondrial DNA lineage and colour morph. Amplified fragment length polymorphism results, based on two primer combinations, were broadly congruent with mitochondrial DNA results with one significant exception. Despite showing over 14% divergence at COI, amplified fragment length polymorphism markers showed that the two green morph lineages may be interbreeding and therefore represent a single taxon. The cryptic diversity revealed by these results has profound consequences for all areas of earthworm research.
蚯蚓在土壤肥力、食物网生态和生态系统功能的许多方面都发挥着重要作用，因此经常成为例如生态和毒理学研究的对象。我们的目的是研究常见蚯蚓物种的遗传结构，识别可能是不同生态型或生物型的隐性谱系或物种（从而混淆当前基于形态型的研究），并试图解释最终出现的大量隐性多样性。我们证明，诸如绿异唇蚓、长栉盲蚓、玫瑰栉盲蚓和红色正蚓等物种都包含高度分化的谱系，在线粒体细胞色素氧化酶I（COI）基因上存在物种水平的差异。仅在绿异唇蚓中，我们就发现了55种COI单倍型，其中35种存在于粉色形态的蚯蚓中，20种存在于绿色形态的蚯蚓中。没有两种颜色形态共享COI单倍型的情况。线粒体COI和16S基因的系统发育分析表明存在五个高度分化的谱系，这表明绿异唇蚓中存在多个隐性物种。谱系分布没有明显的地理模式，许多种群在线粒体DNA谱系和颜色形态上都是多态的。基于两种引物组合的扩增片段长度多态性结果与线粒体DNA结果大致一致，但有一个显著例外。尽管在COI上显示出超过14%的差异，但扩增片段长度多态性标记表明，两个绿色形态的谱系可能正在杂交，因此代表一个单一分类单元。这些结果揭示的隐性多样性对蚯蚓研究的所有领域都有深远影响。
