Por Mauro Rebelo

Environmental DNA Glossary

  • Environmental DNA (“eDNA”): genetic material, in the form of extracellular DNA, dispersed in the environment, whether in water, soil or air.
  • Complementary DNA (“cDNA”): DNA strand created from the reverse transcription of a messenger RNA or viral RNA, which can then be amplified in the RT-PCR process (polymerase chain reaction, after reverse transcriptase reaction).
  • Metabarcodingmethod that uses next-generation DNA sequencing to characterize communities of organisms by amplifying and identifying “barcodes” to identify them within complex samples.
  • Barcode of lifebarcode of life: small DNA sequences, highly specific to each species of living being, which can be sequenced and compared to databases to identify them.
  • Cytochrome oxidase I (“COI”): currently the most widely accepted gene to be used as a barcode for animal species. More specifically, subunit 1 of the mitochondrial gene of the cytochrome oxidase enzyme.
  • Molecular taxonomy: approach that uses genetic information, such as “barcodes”, to establish the identity or kinship of an organism within a taxonomic level (species, genus, family, …)..
  • Operational taxonomic unit (“OTU”): assignment of sets of DNA sequences, which could not be identified to species level, but which belong to the same taxon (for example: the same family).
  • Next-generation sequencingNext-generation sequencing: a set of parallel, high-throughput sequencing technologies that allow larger DNA fragments to be sequenced faster and in an automated way.
  • MetagenomicsMetagenomics: similar to metabarcoding, but instead of sequencing “barcode” genes, it involves sequencing other stretches of DNA from a sample.
  • Gene flowThe exchange of genetic material within or between populations due to the movement of individuals or gametes.
  • Allelic frequency: one of the tools that can be used to characterize populations. Number of times an allele appears in a population, divided by the total number of copies of the gene in question.