Environmental DNA Flashcards
(7 cards)
Discuss 3 distinct ways that genetic (DNA) data can be used to study marine invertebrates.
For single species detection , community detection, diversity detection.
What is the definition of environmental DNA?
The complex mixture of genomic information that is
released by every organism of the biological community into their environment.
What is the definition of metabarcoding?
The large-scale taxonomic identification of complex
environmental samples via analysis of DNA sequences for short regions of
one or a few genes (DNA barcodes)
Describe eDNA barcoding and monitoring and eDNA metabarcoding
eDNA Barcoding - to circumvent the need for morphological identification, scientists incorporated this molecular approach
eDNA Monitoring and Metabarcoding - Then scientists managed to figure out how to extract DNA from environment samples to circumvent the need for invasive sampling, plus use parallel sequencing approaches to reduce sampling time (metabarcoding)
Detail TWO (2) limitations associated with
eDNA and potential strategies for overcoming these constraints in the future
Contamination, How long the DNA has been where it is
Explain the advantages and disadvantages (associated limitations) of eDNA surveys
Advantages:
- Does not require taxonomic expertise
- Results can be obtained faster, especially for lots of samples or when
targeting “non-charismatic” and multiple taxonomic groups
- No human bias in taxonomic assignment (misidentification)
- Cheaper than traditional methods when scaled
- Non-invasive
Disadvantages:
* Incomplete reference databases can result in low-taxonomic resolution
* Low DNA concentration in samples are prone to contamination risk
* eDNA signal strength – species abundance relationship is not proven
* Difficulties in disentangling trophic levels
* Bioinformatic skills required
What sort of research questions can be answered using genetic data?
Population structure and connectivity Questions
How are populations genetically structured across geographic space?
What are the patterns of gene flow between populations?
Life history and speciation Questions
What are the phylogenetic relationships between species?
How and when did speciation events occur?
Adaptation and selection Questions
How are populations adapting to different environmental conditions?
How has climate change impacted population demographics over time?
What is the level of genetic diversity within endangered populations?
Reproduction and life history:
