DNA barcoding and taxonomy in diptera: A tale of high intraspecific variability and low identification success
DNA barcoding and taxonomy in diptera: A tale of high intraspecific variability and low identification success
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DOI：
10.1080/10635150600969864
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发表时间：
2006-01-01
影响因子：
6.5
通讯作者：
Ng, Peter K. L.
中科院分区：
文献类型：
--
作者：
Meier, Rudolf;Shiyang, Kwong;Ng, Peter K. L.
DNA条形码和DNA分类法最近被提议作为分类危机的解决方案，并受到了科学期刊，赠款机构，自然历史博物馆和主流媒体的极大关注。在这里，我们使用1333个线粒体COI序列测试了分子分类学的两个关键主张，用于449种双翅目。我们研究是否可以用于物种鉴定（“ DNA条形码”），并根据基于树和新提出的物种鉴定标准找到相对较低的成功率（<70％）。误认识是由于内部和种间遗传变异性之间的重叠所致，这会导致所有查询序列的6.5％具有同种和特异性（3.6％）最佳匹配条形码的同种特异性或混合物。即使两个COI序列相同，它们也有6％的机会属于不同的物种。我们还发现，当使用所有同种序列的共识序列时，所有物种中有21％都缺乏独特的条形码。最后，我们测试当基于成对距离阈值组装序列时，DNA序列是否产生明确的物种级分类法。我们发现许多序列三重态，三个成对距离中的两个保持在阈值以下，而第三个序列超过了阈值。即，不可能基于成对距离始终如一地界定物种。此外，对于基于3％阈值的物种剖面，只有47％的所有概况与当前接受的物种限制一致，20％的物种包含多个物种，而33％的物种仅来自一个物种的某些序列；即，采用这种DNA分类法将需要重新描述大部分已知物种，从而使分类学障碍恶化。最后，我们对获得完整的条形码数据库的前景以及在现代综合分类学中的未来使用DNA序列的前景进行了看法。
DNA barcoding and DNA taxonomy have recently been proposed as solutions to the crisis of taxonomy and received significant attention from scientific journals, grant agencies, natural history museums, and mainstream media. Here, we test two key claims of molecular taxonomy using 1333 mitochondrial COI sequences for 449 species of Diptera. We investigate whether sequences can be used for species identification ("DNA barcoding") and find a relatively low success rate (< 70%) based on tree-based and newly proposed species identification criteria. Misidentifications are due to wide overlap between intra- and interspecific genetic variability, which causes 6.5% of all query sequences to have allospecific or a mixture of allo- and conspecific (3.6%) best-matching barcodes. Even when two COI sequences are identical, there is a 6% chance that they belong to different species. We also find that 21% of all species lack unique barcodes when consensus sequences of all conspecific sequences are used. Lastly, we test whether DNA sequences yield an unambiguous species-level taxonomy when sequence profiles are assembled based on pairwise distance thresholds. We find many sequence triplets for which two of the three pairwise distances remain below the threshold, whereas the third exceeds it; i.e., it is impossible to consistently delimit species based on pairwise distances. Furthermore, for species profiles based on a 3% threshold, only 47% of all profiles are consistent with currently accepted species limits, 20% contain more than one species, and 33% only some sequences from one species; i.e., adopting such a DNA taxonomy would require the redescription of a large proportion of the known species, thus worsening the taxonomic impediment. We conclude with an outlook on the prospects of obtaining complete barcode databases and the future use of DNA sequences in a modern integrative taxonomy.