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1 1 (December 15, 2022)

handle is hein.crs/govejuj0001 and id is 1 raw text is: Congressional Research Service inforrning the Iegislative debate since 1914 December 15, 2022 eDNA/eRNA: Scientific Value in What's Left Behind Environmental deoxyribonucleic acid (eDNA) and environmental ribonucleic acid (eRNA) are trace amounts of genetic material collected from an environmental sample, such as from soil, terrestrial and aquatic sediments, freshwater, seawater, wastewater, or air. This genetic material can come from shed skin, hair, and other cells; secreted waste or mucus; and carcasses, among other biological sources. It can provide information on the recent presence of organisms where a sample was collected without directly observing the organisms. Multiple federal agencies have begun using eDNA/eRNA for various research, monitoring, and decisionmaking purposes. Decreased costs and increased access to eDNA/eRNA analysis technologies have also allowed other entities to develop monitoring projects and programs. H ow It Work(s To analyze eDNA/eRNA, researchers extract partial DNA/RNA from an environmental sample, amplify it (make copies), and compare it against a reference sequence from a previously sequenced organism in order to make a positive match. Depending on research needs, different types of eDNA/eRNA analyses can be performed on an environmental sample (see Figure 1). For example, a targeted analysis aims to detect a particular species with high accuracy. Alternatively, a non-targeted approach, a method referred to as metabarcoding, can more broadly characterize the various different species whose DNA/RNA is found in the sample. Figure I. eDNA Sampling in Aquatic Environments 1. Water sample collection 2. Sample Filtration Species-specific :detection - c~cAGAGacTA~sAa4 eDNA -c Nd metabarcoding c detection 4 5. eDNA sequencing and data analysis 4. DNA Amplification 3 DNA Extraction Source: Songqian Huang, Kazutoshi Yoshitake, and Shugo Watabe, et al., Environmental DNA Study on Aquatic Ecosystem Monitoring and Management: Recent Advances and Prospects, Journal of Environmental Management, vol. 323, no. 116310 (2022). eDNA/eRNA Reference Databases The availability and quality of a reference sequence can affect the analysis of and ability for an eDNA/eRNA sample to be used for various research and decisionmaking purposes. For example, accurate identification of a particular species requires reference sequences of sufficient quality to exist and be available. Individual databases have varying standards that govern access as well as the type and quality of information they contain. Therefore, the design, management, quality standards, and data protocols for reference databases can affect eDNA/eRNA's utility. Databases containing certain genetic sequence information, such as for viruses, can also have implications for biosafety and biosecurity, depending on who has access to sequences and if their use is regulated. Some federal agencies are developing, or already have, databases for eDNA/eRNA analysis. For example, the U.S. Geological Survey (USGS) has, and plans to develop, databases for eDNA that include assays and genetic markers. The Aquatic eDNAtlas Project, managed by the U.S. Forest Service National Genomics Center for Fish and Wildlife Conservation, is a database that provides information on eDNA sampling detection/nondetection results for freshwater species in the United States. The database, updated annually, contains over 20,000 data points. Natural resource agencies and nongovernmental organizations use a standardized field sampling protocol to gather and enter environmental samples for the database. Nonfederal entities-such as universities, private companies, and international organizations-also compile their own databases of species sequences. For example, the International Barcode of Life (iBOL) is an international research consortium developing DNA reference libraries, sequencing facilities, informatics platforms, and analytical protocols to help inventory and assess biodiversity. iBOL has entered sequences from 500,000 species into reference libraries and intends to add another 2.5 million species by 2026. eDNA for Environmental Monitoring Federal agencies use eDNA for various monitoring purposes. eDNA data can provide information on the presence or absence, geographic distribution and range, relative abundance, and status of organisms. Applications include tracking species of interest, such as particular native species, tracking protected species for species assessment and conservation purposes; identifying the presence of small or rare (lesser known) species that are difficult to observe directly; and detecting the presence of non-native species that may adversely affect ecosystems. eDNA analysis can be limited in its ability to determine how many of a particular species may be in the study area. eDNA data also cannot determine with certainty whether a particular species was located in the sampling area at the

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