Evidence of hidden biodiversity, ongoing speciation and diverse patterns of genetic structure in giant Antarctic amphipods
Evidence of hidden biodiversity, ongoing speciation and diverse patterns of genetic structure in giant Antarctic amphipods
复制标题
DOI：
10.1111/j.1365-294x.2011.05173.x
复制
发表时间：
2011-08-01
影响因子：
4.9
通讯作者：
Stark, Jonathan S.
中科院分区：
文献类型：
--
作者：
Baird, Helena P.;Miller, Karen J.;Stark, Jonathan S.
最近对南极底栖生物的分子研究对传统的生物分类学提出了挑战，这表明我们目前对南极生物多样性和物种分布的看法必须彻底改变。此外，种内遗传分化仍然知之甚少，特别是在南极洲东部。我们解决了这些问题，使用DNA序列数据的两个兄弟姐妹片脚类动物物种，可以收集到一个环南极的规模：Eusirus perdentatus和Eusirus carteus。基于线粒体（COI，CytB）和细胞核（ITS 2）DNA的单倍型网络和贝叶斯遗传学提供了强有力的证据，证明了Eusirus的多个神秘物种，其中几个出现在同域分布中，至少有一个可能具有真正的环南极分布。在物种内部，基因流动往往受到高度限制，这与一个沉思的生活史相一致，在某些情况下，暗示着当前或未来的异域物种形成。遗传结构的模式并不总是可预测的：一个神秘的物种在南极洲东部显示出类似于150 km的高度遗传分化的初步证据（F-ST > 0.47，P < 0.01），而另一个物种在类似于5000 km的高度遗传分化非常均匀（F-ST = 0.00，P = 1.00）。隐种间的遗传多样性也各不相同，与样本大小无关（pi = 0.00-0.99）。这些结果表明，在这些南极端足类动物的遗传复杂性，既不明显，从以前的分类或生态研究，也不从他们的生活史可预测的几个隐藏的水平。这种遗传多样性和结构可能反映了南极底栖生物在历史冰川周期中的不同生存模式，和/或随后在大陆架上重新建立种群，并突出了我们对南极海洋物种多样性的误解。
Recent molecular research on Antarctic benthic organisms has challenged traditional taxonomic classifications, suggesting that our current perceptions of Antarctic biodiversity and species distributions must be thoroughly revised. Furthermore, genetic differentiation at the intraspecific level remains poorly understood, particularly in eastern Antarctica. We addressed these issues using DNA sequence data for two sibling amphipod species that could be collected on a circum-Antarctic scale: Eusirus perdentatus and Eusirus giganteus. Haplotype networks and Bayesian phylogenies based on mitochondrial (COI, CytB) and nuclear (ITS2) DNA provided strong evidence of multiple cryptic species of Eusirus, with several occurring in sympatry and at least one likely to have a true circum- Antarctic distribution. Within species, gene flow was often highly restricted, consistent with a brooding life history and in some cases suggestive of current or future allopatric speciation. Patterns of genetic structure were not always predictable: one cryptic species showed preliminary evidence of high genetic differentiation across similar to 150 km in eastern Antarctica (F-ST > 0.47, P < 0.01), yet another was remarkably homogenous across similar to 5000 km (F-ST = 0.00, P = 1.00). Genetic diversity also varied among cryptic species, independent of sample size (pi = 0.00-0.99). These results indicate several hidden levels of genetic complexity in these Antarctic amphipods that are neither apparent from previous taxonomic or ecological studies nor predictable from their life history. Such genetic diversity and structure may reflect different modes of survival for Antarctic benthic organisms during historic glacial cycles, and/or subsequent re-establishment of populations on the shelf, and highlight our misunderstanding of Antarctic marine species diversity.