Hundreds of new DNA barcodes for South African sponges

DNA barcoding based on a fragment of the cytochrome c oxidase subunit I (COI) gene from the mitochondrial genome is widely applied in species identification, species discovery and biodiversity studies. The aim of this study was to establish a barcoding reference database of sponges collected from South Africa, and evaluate the applicability of the COI gene for aiding in the identification of sponges in combination with tentative morphological identifications. A total of 317 mitochondrial COI barcode sequences, with an additional 21 extended COI fragments and 24 nuclear ITS sequences, were obtained from 11 orders, 38 families, 58 genera and 124 species of spiculated sponges. A Neighbour Joining (NJ) trees that were reconstructed using these sequences in most cases clustered species in accordance with their current taxonomic identification, and we conclude that COI sequencing can be used to aid in the identification of sponge species. We further demonstrate that DNA barcoding analysis has potential to uncover cryptic sponge species, and to reveal dubious morphological identifications. We recommend that future taxonomic studies of South African sponges incorporate multiple sources of information for species identification or discovery.

基于线粒体基因组细胞色素c氧化酶亚基I（cytochrome c oxidase subunit I, COI）基因片段的DNA条形码（DNA barcoding）技术，已被广泛应用于物种鉴定、物种发现及生物多样性研究领域。本研究旨在构建一套采自南非的海绵条形码参考数据库，并结合初步形态学鉴定结果，评估COI基因在辅助海绵物种鉴定中的适用性。本研究从11目、38科、58属共124种骨针海绵中，共获得317条线粒体COI条形码序列，另有21条延伸COI片段序列及24条细胞核ITS序列。基于上述序列构建的邻接（Neighbour Joining, NJ）系统发育树，在多数情况下可依据当前分类学鉴定结果对物种进行聚类，本研究证实COI测序可用于辅助海绵物种的鉴定。本研究进一步证明，DNA条形码分析具有发掘隐蔽海绵物种、揭示可疑形态学鉴定结果的潜力。我们建议未来针对南非海绵的分类学研究，应整合多源信息以开展物种鉴定或发现工作。