Evaluating alternative hypotheses for the early evolution and diversification of ants
Evaluating alternative hypotheses for the early evolution and diversification of ants
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DOI：
10.1073/pnas.0605858103
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发表时间：
2006-11-28
影响因子：
11.1
通讯作者：
Ward, Philip S.
中科院分区：
文献类型：
--
作者：
Brady, Sean G.;Schultz, Ted R.;Ward, Philip S.
蚂蚁是世界上种类最多、生态优势最强的生态社会性生物。解决主要蚂蚁谱系的系统发育和时间尺度对于理解它们是如何取得这一成功至关重要的。然而，形态、分子和古生物学研究对早期蚂蚁进化提出了相互矛盾的观点。为了解决这些问题，我们生成了迄今为止发表的最大的蚂蚁分子系统发育数据集，包含来自162个物种的近6kb的DNA序列，代表所有20个蚂蚁亚科和10个针状外群家族。当分析这些数据时，我们得到了一些早期蚂蚁谱系的相互冲突的群内拓扑结构，这些外群都与蚂蚁有很远的亲缘关系，因此是长分支的。这一结果使人们对目前定义的滑石支系的存在产生了强烈的怀疑。我们通过使用似然检验来比较外群和内群树的替换附着，并且发现数据不能拒绝几个替换根。对于蚂蚁形态和行为的早期进化，这些替代方案意味着根本不同的情景。我们的数据有力地支持了更多起源类蚂蚁之间的几个值得注意的关系，包括将神秘的Aenictogitinae亚家族定位为Dorylus军蚁的姐妹。我们使用分子数据来估计分歧时间，采用了一种与以前的工作不同的策略，包括了其他有刺的膜翅目以及蚂蚁的大量化石记录。我们对现存物种最近共同祖先的年龄估计从大约1.15亿年到1.35亿年前不等，这表明侏罗纪起源的可能性很小。
Ants are the world's most diverse and ecologically dominant eusocial organisms. Resolving the phylogeny and timescale for major ant lineages is vital to understanding how they achieved this success. Morphological, molecular, and paleontological studies, however, have presented conflicting views on early ant evolution. To address these issues, we generated the largest ant molecular phylogenetic data set published to date, containing approximate to 6 kb of DNA sequence from 162 species representing all 20 ant subfamilies and 10 aculeate outgroup families. When these data were analyzed with and without outgroups, which are all distantly related to ants and hence long-branched, we obtained conflicting ingroup topologies for some early ant lineages. This result casts strong doubt on the existence of a poneroid clade as currently defined. We compare alternate attachments of the outgroups to the ingroup tree by using likelihood tests, and find that several alternative rootings cannot be rejected by the data. These alternatives imply fundamentally different scenarios for the early evolution of ant morphology and behavior. Our data strongly support several notable relationships within the more derived formicoid ants, including placement of the enigmatic subfamily Aenictogitoninae as sister to Dorylus army ants. We use the molecular data to estimate divergence times, employing a strategy distinct from previous work by incorporating the extensive fossil record of other aculeate Hymenoptera as well as that of ants. Our age estimates for the most recent common ancestor of extant ants range from approximate to 115 to 135 million years ago, indicating that a Jurassic origin is highly unlikely.