Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843-4458, USA.
Genome Res. 2011 Oct;21(10):1695-704. doi: 10.1101/gr.120196.111. Epub 2011 Aug 31.
The ability to uncover the phylogenetic history of recently extinct species and other species known only from archived museum material has rapidly improved due to the reduced cost and increased sequence capacity of next-generation sequencing technologies. One limitation of these approaches is the difficulty of isolating and sequencing large, orthologous DNA regions across multiple divergent species, which is exacerbated for museum specimens, where DNA quality varies greatly between samples and contamination levels are often high. Here we describe the use of cross-species DNA capture hybridization techniques and next-generation sequencing to selectively isolate and sequence partial to full-length mitochondrial DNA genomes from the degraded DNA of museum specimens, using probes generated from the DNA of a single extant species. We demonstrate our approach on specimens from an enigmatic gliding mammal, the Sunda colugo, which is widely distributed throughout Southeast Asia. We isolated DNA from 13 colugo specimens collected 47-170 years ago, and successfully captured and sequenced mitochondrial DNA from every specimen, frequently recovering fragments with 10%-13% sequence divergence from the capture probe sequence. Phylogenetic results reveal deep genetic divergence among colugos, both within and between the islands of Borneo and Java, as well as between the Malay Peninsula and different Sundaic islands. Our method is based on noninvasive sampling of minute amounts of soft tissue material from museum specimens, leaving the original specimen essentially undamaged. This approach represents a paradigm shift away from standard PCR-based approaches for accessing population genetic and phylogenomic information from poorly known and difficult-to-study species.
由于下一代测序技术成本降低和序列容量增加,揭示最近灭绝物种和其他仅从存档的博物馆材料中了解的物种的系统发育历史的能力得到了迅速提高。这些方法的一个限制是,很难在多个不同物种之间隔离和测序大型、直系同源的 DNA 区域,对于博物馆标本来说,这一问题更加严重,因为 DNA 质量在样本之间差异很大,污染水平通常很高。在这里,我们描述了使用跨物种 DNA 捕获杂交技术和下一代测序技术,从博物馆标本的降解 DNA 中选择性地分离和测序部分至全长线粒体 DNA 基因组的方法,使用从单个现存物种的 DNA 生成的探针。我们使用分布广泛的东南亚神秘滑翔哺乳动物巽他飞狐的标本来证明我们的方法。我们从 47 到 170 年前收集的 13 个巽他飞狐标本中分离出 DNA,并成功地从每个标本中捕获和测序了线粒体 DNA,经常从捕获探针序列中恢复 10%-13%序列差异的片段。系统发育结果揭示了巽他飞狐之间的深刻遗传分歧,包括婆罗洲和爪哇岛内部和之间,以及马来半岛和不同巽他群岛之间。我们的方法基于从小量的博物馆标本的软组织材料进行非侵入性采样,使原始标本基本不受损坏。这种方法代表了一种从标准 PCR 方法转变而来的方法,用于从了解甚少和难以研究的物种中获取群体遗传和系统基因组信息。