Dataset Information

Genome skimming and exploration of DNA barcodes for Taiwan endemic cypresses.

ABSTRACT: Cypresses are characterized by their longevity and valuable timber. In Taiwan, two endemic cypress species, Chamaecyparis formosensis and C. obtusa var. formosana, are threatened by prevalent illegal logging. A DNA barcode system is urgently needed for reforestation and conservation of these two cypresses. In this study, both plastomes and 35S rDNAs from 16, 10, and 6 individuals of C. formosensis, C. obtusa var. formosana, and C. obtusa var. obtusa were sequenced, respectively. We show that the loss of plastid trnT-GGU readily distinguishes C. formosensis from its congeneric species. We demonstrate that entire sequences of plastomes or 35S rDNAs are capable of correctly identifying cypress species and varieties, suggesting that they are effective super-barcodes. We also discover three short hypervariable loci (i.e., 3'ETS, ITS1, and trnH-psbA) that are promising barcodes for identifying cypress species and varieties. Moreover, nine species-specific indels of?>?100 bp were detected in the cypress plastomes. These indels, together with the three aforementioned short barcodes, constitute an alternative and powerful barcode system crucial for identifying specimens that are fragmentary or contain degraded/poor DNA. Our sequenced data and barcode systems not only enrich the genetic reference for cypresses, but also contribute to future reforestation, conservation, and forensic investigations.

SUBMITTER: Wu CS

PROVIDER: S-EPMC7693304 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Publications

Genome skimming and exploration of DNA barcodes for Taiwan endemic cypresses.

Wu Chung-Shien CS Sudianto Edi E Hung Yu-Mei YM Wang Bo-Cyun BC Huang Chiun-Jr CJ Chen Chi-Tsong CT Chaw Shu-Miaw SM

Scientific reports 20201126 1

Cypresses are characterized by their longevity and valuable timber. In Taiwan, two endemic cypress species, Chamaecyparis formosensis and C. obtusa var. formosana, are threatened by prevalent illegal logging. A DNA barcode system is urgently needed for reforestation and conservation of these two cypresses. In this study, both plastomes and 35S rDNAs from 16, 10, and 6 individuals of C. formosensis, C. obtusa var. formosana, and C. obtusa var. obtusa were sequenced, respectively. We show that the ...[more]

PMID: 33244113

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Project description:DNA barcoding is critical to conservation and biodiversity research, yet public reference databases are incomplete. Existing barcode databases are biased toward cytochrome oxidase subunit I (COI) and frequently lack associated voucher specimens or geospatial metadata, which can hinder reliable species assignments. The emergence of metabarcoding approaches such as environmental DNA (eDNA) has necessitated multiple marker techniques combined with barcode reference databases backed by voucher specimens. Reference barcodes have traditionally been generated by Sanger sequencing, however sequencing multiple markers is costly for large numbers of specimens, requires multiple separate PCR reactions, and limits resulting sequences to targeted regions. High-throughput sequencing techniques such as genome skimming enable assembly of complete mitogenomes, which contain the most commonly used barcoding loci (e.g., COI, 12S, 16S), as well as nuclear ribosomal repeat regions (e.g., ITS1&2, 18S). We evaluated the feasibility of genome skimming to generate barcode references databases for marine fishes by assembling complete mitogenomes and nuclear ribosomal repeats. We tested genome skimming across a taxonomically diverse selection of 12 marine fish species from the collections of the National Museum of Natural History, Smithsonian Institution. We generated two sequencing libraries per species to test the impact of shearing method (enzymatic or mechanical), extraction method (kit-based or automated), and input DNA concentration. We produced complete mitogenomes for all non-chondrichthyans (11/12 species) and assembled nuclear ribosomal repeats (18S-ITS1-5.8S-ITS2-28S) for all taxa. The quality and completeness of mitogenome assemblies was not impacted by shearing method, extraction method or input DNA concentration. Our results reaffirm that genome skimming is an efficient and (at scale) cost-effective method to generate all mitochondrial and common nuclear DNA barcoding loci for multiple species simultaneously, which has great potential to scale for future projects and facilitate completing barcode reference databases for marine fishes.

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Dataset Information

Genome skimming and exploration of DNA barcodes for Taiwan endemic cypresses.

Publications

Genome skimming and exploration of DNA barcodes for Taiwan endemic cypresses.

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