Schlötterer C, Amos B, Tautz D
Institut für Genetik und Mikrobiologie, Universität München, Germany.
Nature. 1991 Nov 7;354(6348):63-5. doi: 10.1038/354063a0.
Length polymorphisms within simple-sequence loci occur ubiquitously in non-coding eukaryotic DNA and can be highly informative in the analysis of natural populations. Simple-sequence length polymorphisms (SSLP) in the long-finned pilot whale Globicephala melas (Delphinidae) have provided useful information on the mating system as well as on the genetic structure of populations. We have therefore tested whether the polymerase chain reaction primers designed for Globicephala could also be used to uncover variability in other whale species. Homologous loci could indeed be amplified from a diverse range of whales, including all toothed (Odontoceti) and baleen whales (Mysticeti) tested. Cloning and sequencing these loci from 11 different species revealed an unusually high conservation of sequences flanking the simple-sequence stretches, averaging 3.2% difference over 35-40 Myr. This represents the lowest divergence rate for neutral nucleotide positions found for any species group so far and raises the possible need for a re-evaluation of the age of the modern whales. On the other hand, the high conservation of non-coding sequences in whales simplifies the application of SSLP DNA fingerprinting in cetacean species, as primers designed for one species will often uncover variability in other species.
简单序列位点内的长度多态性在非编码真核生物DNA中普遍存在，并且在自然种群分析中可能具有很高的信息量。长鳍领航鲸（Globicephala melas，海豚科）中的简单序列长度多态性（SSLP）为交配系统以及种群的遗传结构提供了有用信息。因此，我们测试了为长鳍领航鲸设计的聚合酶链反应引物是否也可用于揭示其他鲸类物种的变异性。实际上，可以从多种鲸类中扩增出同源位点，包括所有测试的齿鲸（Odontoceti）和须鲸（Mysticeti）。对11个不同物种的这些位点进行克隆和测序发现，简单序列片段侧翼的序列具有异常高的保守性，在3500万至4000万年的时间里平均差异为3.2%。这代表了迄今为止在任何物种组中发现的中性核苷酸位置的最低分歧率，并引发了对现代鲸类年龄重新评估的可能需求。另一方面，鲸类中非编码序列的高度保守性简化了SSLP DNA指纹图谱在鲸类物种中的应用，因为为一个物种设计的引物通常会揭示其他物种的变异性。
