Data from: Moorean and Tahitian Partula tree snail survival after a mass extinction: new genomic insights using museum specimens

Natural history museum collections provide a biodiversity window into the past and are of particular importance to the study of extinction-impacted clades such as the Pacific Island tree snail family Partulidae. Deliberate introduction of the predatory rosy wolf snail Euglandina rosea in the late 20th century led to the extinction/extirpation of 55/61 Society Island Partulidae species. In this study, we phylogenomically investigated the inter-relationships of the three surviving Society Island valley Partula species: P. taeniata (Moorea), P. clara and P. hyalina (Tahiti). All three formed a distinct clade in earlier mitochondrial phylogenies. Using Next Generation Sequencing (NGS) double digested Restriction Associated DNA sequencing (ddRADseq), we found that 46-year-old lyophilized museum specimens produced similar numbers of reads, sequencing depth, and loci as 10-year old ethanol-preserved collections. Phylogenomic trees indicated that Tahitian P. clara and P. hyalina are the result of a single founding lineage from Moorea, contrasting previous mitochondrial results and clarifying the enigmatic taxonomic status of P. c. incrassa. Our study highlights the utility and viability of NGS techniques for museum specimens and their increased resolution of evolutionary patterns. Sampling will be expanded to include the remaining Society Island partulid taxa to further explore the evolutionary history of this radiation.

自然历史博物馆馆藏是窥探过去生物多样性的重要窗口，对于受灭绝影响的演化支（如太平洋岛屿树蜗牛科（Partulidae））的研究具有特殊重要意义。20世纪末，人为引入掠食性玫瑰狼蜗牛（Euglandina rosea），致使社会群岛内55/61个该科物种灭绝或局部灭绝。本研究采用系统基因组学方法，探究了社会群岛山谷中现存的3种树蜗牛属（Partula）物种的亲缘关系：分别为莫雷阿岛的P. taeniata，以及塔希提岛的P. clara与P. hyalina。此前的线粒体系统发育研究显示，这三个物种构成了一个独立的演化支。本研究借助下一代测序（Next Generation Sequencing, NGS）技术中的双酶切限制性位点相关DNA测序（double digested Restriction Associated DNA sequencing, ddRADseq），发现46年历史的冷冻干燥博物馆标本，其获得的测序读段数、测序深度以及基因位点数，与10年历史的乙醇保存标本无显著差异。系统发育树分析结果表明，塔希提岛的P. clara与P. hyalina均起源于莫雷阿岛的单一奠基谱系，这一结论与此前的线粒体研究结果相悖，同时阐明了P. c. incrassa悬而未决的分类学地位。本研究凸显了下一代测序技术在博物馆标本研究中的实用性与可行性，同时证实其可提升演化模式解析的分辨率。后续研究将扩大采样范围，纳入社会群岛内其余该类群的分类单元，以进一步探究该辐射演化类群的演化历史。