Metabarcoding is a way of quickly and cheaply generating diversity data for entire communities, so that they can be compared across time and space.
This approach is invaluable where the local biota is poorly known or understudied, or when the aim is to demonstrate the response of biological communities to impacts such as pollution, land-use change or conservation and management interventions. Local reference databases can be used to give high confidence identifications for taxa of particular interest.
Metabarcoding can be applied to bulk samples of organisms when taxonomic expertise is lacking (e.g. unsorted insect trap samples), or to eDNA samples - sequencing all the DNA captured in the sample rather than just screening for the presence of one species, as with qPCR.
Here's a simplified representation of a metabarcoding pipeline:
Contact us to discuss your metabarcoding requirements. Prices range from £100 - £300 per unsorted collection depending on requirements.
Metabarcoding is an extension of the more familiar DNA barcoding approach, which identifies species by sequencing a standardised region of DNA and comparing it against reference databases. Barcode regions are sections of DNA that vary little among individuals from the same species but vary extensively among individuals of different (even closely related) species. They are said to be ‘diagnostic at the species level’. Crucially, DNA barcoding overcomes the taxonomic impediment by moving away from morphology-based identification, meaning that specimens can be identified at all life stages and regardless of indistinguishable morphology.
DNA barcoding has proved to useful for a wide variety of applications – from identifying specimens in ecological samples to detecting labelling fraud in on-the-shelf products. However, because it requires each specimen to be processed in a separate reaction, it remains prohibitively time consuming and expensive for the purposes of generating large-scale biodiversity data, which may require the processing of hundreds, thousands – or even millions– of specimens.
In recent years, a solution has arisen with the widespread availability and decreasing cost of high-throughput or ‘next generation’ sequencing, which allows the barcodes of very large numbers of specimens/species to be sequenced together in a single reaction. Originally developed for the microbial studies, this approach has become known as DNA ‘metabarcoding’ when applied to multicellular organisms.
The most linear extension of traditional barcoding to metabarcoding is to progress from extraction and sequencing of DNA from individual organisms to bulk extraction and parallel sequencing of DNA from unsorted mixtures of organisms. Informally, we call this method ‘biodiversity soup’ because you first make a ‘soup’ by blending together the contents of your sample and then sequence the mixture of DNA that is extracted from the soup. Such is the power of the approach that over 100 soups can be sequenced in parallel on a single run of the sequencer.
Several studies have demonstrated that the majority of species in a sample can be recovered using metabarcoding (Hajibabaei et al., 2011; Yu et al., 2012; Carew et al., 2013), and that ecological information is recovered accurately (Yu et al., 2012; Ji et al., 2013). Metabarcoding enables the responses of thousands of species to be assessed quickly and cheaply, yielding high-resolution data on environmental change over time and space.