Wild specimens are often collected in challenging field conditions, where samples may be contaminated with the DNA of conspecific individuals. This contamination can result in false genotype calls, which are difficult to detect, but may also cause inaccurate estimates of heterozygosity, allele frequencies and genetic differentiation. Marine broadcast spawners are especially problematic, because population genetic differentiation is low and samples are often collected in bulk and sometimes from active spawning aggregations. Here, we used contaminated and clean Pacific herring (
Advances in environmental DNA (eDNA) methodologies have led to improvements in the ability to detect species and communities in aquatic environments, yet the majority of studies emphasize biological diversity at the species level by targeting variable sites within the mitochondrial genome. Here, we demonstrate that eDNA approaches also have the capacity to detect intraspecific diversity in the nuclear genome, allowing for assessments of population‐level allele frequencies and estimates of the number of genetic contributors in an eDNA sample. Using a panel of microsatellite loci developed for the round goby (
- NSF-PAR ID:
- 10405001
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Molecular Ecology
- Volume:
- 30
- Issue:
- 3
- ISSN:
- 0962-1083
- Page Range / eLocation ID:
- p. 685-697
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Environmental DNA (eDNA) sampling—the detection of genetic material in the environment to infer species presence—has rapidly grown as a tool for sampling aquatic animal communities. A potentially powerful feature of environmental sampling is that all taxa within the habitat shed DNA and so may be detectable, creating opportunity for whole‐community assessments. However, animal DNA in the environment tends to be comparatively rare, making it necessary to enrich for genetic targets from focal taxa prior to sequencing. Current metabarcoding approaches for enrichment rely on bulk amplification using conserved primer annealing sites, which can result in skewed relative sequence abundance and failure to detect some taxa because of PCR bias. Here, we test capture enrichment via hybridization as an alternative strategy for target enrichment using a series of experiments on environmental samples and laboratory‐generated, known‐composition DNA mixtures. Capture enrichment resulted in detecting multiple species in both kinds of samples, and postcapture relative sequence abundance accurately reflected initial relative template abundance. However, further optimization is needed to permit reliable species detection at the very low‐DNA quantities typical of environmental samples (<0.1 ng DNA). We estimate that our capture protocols are comparable to, but less sensitive than, current PCR‐based eDNA analyses.
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