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Environmental DNA or eDNA is DNA that is collected from a variety of environmental samples such as soil, seawater, or even air [1] rather than directly sampled from an individual organism. As various organisms interact with the environment, DNA is expelled and accumulates in their surroundings. Example sources of eDNA include, but are not limited to, feces, mucus, gametes, shed skin, carcasses and hair. [2] Such samples can be analyzed by high-throughput DNA sequencing methods, known as metagenomics, for rapid measurement and monitoring of biodiversity. The analysis of eDNA has great potential, not only for monitoring common species, but to genetically detect and identify other extant species that could influence conservation efforts.[3] This method allows for biomonitoring without requiring collection of the living organism, creating the ability to study organisms that are invasive, elusive, or endangered without introducing anthropogenic stress on the organism. Access to this genetic information makes a critical contribution to the understanding of population size, species distribution, and population dynamics for species not well documented. The integrity of eDNA samples is dependent upon its preservation within the environment. Soil, permafrost, freshwater and seawater are well-studied macro environments from which eDNA samples have been extracted, each of which include many more conditioned subenvironments.[4]
Collection
[edit]Ancient environments
[edit]Terrestrial sediments
[edit]The importance of eDNA analysis stemmed from the recognition of the limitations presented by culture-based studies.[3] Organisms have adapted to thrive in the specific conditions of their natural environments. Although scientists work to mimic these environments, many microbial organisms can not be removed and cultured in a laboratory setting.[4] The genetic makeup of some microbes is then only accessible through eDNA analysis. Analytical techniques of eDNA were first applied to terrestrial sediments yielding DNA from both extinct and extant mammals, birds, insects and plants.[5] Samples extracted from these terrestrial sediments are commonly referenced as 'sedimentary ancient DNA' (sedaDNA or dirtDNA).[6]
See also
[edit]References
[edit]- ^ Ficetola, Gentile Francesco; Miaud, Claude; Pompanon, François; Taberlet, Pierre (2008). "Species detection using environmental DNA from water samples". Biology Letters. 4 (4): 423–425. doi:10.1098/rsbl.2008.0118. ISSN 1744-9561. PMC 2610135. PMID 18400683.
- ^ "What is eDNA?". Freshwater Habitats Trust.
- ^ a b Bohmann, Kristine; Evans, Alice; Gilbert, M. Thomas P.; Carvalho, Gary R.; Creer, Simon; Knapp, Michael; Yu, Douglas W.; de Bruyn, Mark (2014-06-01). "Environmental DNA for wildlife biology and biodiversity monitoring". Trends in Ecology & Evolution. 29 (6): 358–367. doi:10.1016/j.tree.2014.04.003. ISSN 1872-8383. PMID 24821515.
- ^ a b Thomsen, Philip Francis; Willerslev, Eske (2015-03-01). "Environmental DNA – An emerging tool in conservation for monitoring past and present biodiversity". Biological Conservation. Special Issue: Environmental DNA: A powerful new tool for biological conservation. 183: 4–18. doi:10.1016/j.biocon.2014.11.019.
- ^ Willerslev, Eske; Hansen, Anders J.; Binladen, Jonas; Brand, Tina B.; Gilbert, M. Thomas P.; Shapiro, Beth; Bunce, Michael; Wiuf, Carsten; Gilichinsky, David A. (2003-05-02). "Diverse Plant and Animal Genetic Records from Holocene and Pleistocene Sediments". Science. 300 (5620): 791–795. doi:10.1126/science.1084114. ISSN 0036-8075. PMID 12702808. S2CID 1222227.
- ^ Andersen, Kenneth; Bird, Karen Lise; Rasmussen, Morten; Haile, James; Breuning-Madsen, Henrik; Kjaer, Kurt H.; Orlando, Ludovic; Gilbert, M. Thomas P.; Willerslev, Eske (2012-04-01). "Meta-barcoding of 'dirt' DNA from soil reflects vertebrate biodiversity". Molecular Ecology. 21 (8): 1966–1979. doi:10.1111/j.1365-294X.2011.05261.x. ISSN 1365-294X. PMID 21917035. S2CID 43351435.