Leaf-green whole genome and rDNA sequence data.

There are about 3,400 plant specimens in the world, and the total number of specimens currently collected is more than 350 million.
these specimens collect almost all the species that are locally distributed, and together they cover largely the world's known plant species.
collection of specimens have been classified and identified, containing rich species information, of which the pattern specimen is the direct carrier of scientific nouns (names) of each species.
due to the characteristics of plant materials, drying conditions, storage time and other factors, the specimen DNA is highly degraded, the dna extraction concentration is low, and vulnerable to external DNA contamination.
this makes it difficult to extract the specimen's DNA, PCR amplification of the target fragment, and Sanger sequencing.
Although there is great potential for research and application value of specimens, the acquisition of genetic information of specimens lags behind.
the Li Debah Research Group and Molecular Biology Experimental Center of the Plant Diversity and Genomics Research Group of the Kunming Institute of Plant Research, Kunming Institute of Plant Research, Chinese Academy of Sciences, have been working on plant DNA barcode and genomics research for many years.
next-generation sequencing technology (Next Sequencing) brings new opportunities for the acquisition of genetic information on specimens, as the next generation of sequencing technology is a template for building libraries with 100-400 bp short segment molecules. At the same time, genome shallow sequencing (Genome Skimming) obtains genome-wide lower sequencing depth genomic data through second-generation sequencing technology, and bioinformatics enables the acquisition of sequence data such as chlorophyll whole genomes, mitochondria, and highly repetitive regions of the nuclear genome, such as rDNA.

recently, the team, with the support of the Molecular Biology Laboratory, in collaboration with the Royal Botanic Gardens in Edinburgh, took into account the integrity, scarcity and irreplaceable nature of the specimen, and attempted to select a 500 pg of the initial DNA (mostly ng or sg) and, through the optimization of the library construction process, successfully obtained the specimen's chlorophyll whole genome and rDNA sequence data for DNA barcode 2.0 and systematic developmental genomics research.
studies have found that with 500 pg as the starting amount, the template molecules are not interrupted, no fragment selection is made, and no less than 8 PCR cycle-rich barcode libraries can be used as a standard process for the construction of low-quality sample libraries.
tested 25 specimens (collected from 1934-2007), 23 specimens were able to obtain a complete or nearly complete chloroplast genome sequence, and 21 specimens were able to obtain rDNA sequences.
at present, the Molecular Biology Experimental Center has formed the standards and technical specifications for the construction of low-quality sample libraries, as well as data assembly and stitching specifications.
a wide range of applications based on specimen-based techniques for obtaining chlorophyll whole genome and rDNA sequence data, including: (1) various plant products (e.g. wood, bark, powder, herbal medicine, tablets, etc.) for highly degradable DNA, as well as plant roots, animal digests, etc. (2) integrating the genetic information of the model specimen into the existing classification framework, (3) obtaining genetic information from the specimen that is no longer available to collect even extinct species in the wild, and (4) obtaining genetic information from the specimen to assess the loss or change of genetic diversity caused by environmental changes.
's research was published in the international journal Plant Methods for Botany Research, based on Genome skimming herbarium specimens for DNA barcoding and phylogenomics.
the research was supported by the Special Project of Science and Technology Basic Work (2013FY112600), the Chinese Academy of Sciences' Open Science and Technology Infrastructure Research Project (2017-LSF-GBOWS-02) and the Biodiversity Conservation Strategy Project (ZSSD-011) of the Strategic Biological Resources Services Network Program of the Chinese Academy of Sciences.
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