Qualitative and quantitative DNA metabarcoding assessment of Neotropical
ichthyoplankton communities is marker-dependent
Abstract
The study of ichthyoplankton is paramount to understanding fish
assemblages’ reproductive dynamics. DNA metabarcoding has been applied
as a rapid, cost-effective, and accurate taxonomy tool, allowing the
identification of multiple individuals simultaneously. However, there
remain significant challenges when using DNA metabarcoding, such as
molecular marker choice according to the taxonomic resolution and length
of the fragment to be sequenced, primer bias, incomplete reference
databases, and qualitative inferences incongruences. Here, 30
ichthyoplankton pools collected from a Neotropical River were identified
at a molecular level using DNA metabarcoding to compare the resolution,
sensibility, specificity and relative read abundance (RRA) recovery of
three molecular markers: the standard COI fragment (650pb, with each
strand analyzed individually) and two short 12S rRNA genes markers (
200bp - NeoFish and MiFish markers). The combined use of the three
markers increased the genera detection rates by 25% to 87.5%, allowing
an increased taxonomic coverage and robust taxonomic identification of
complex neotropical ichthyoplankton communities. RRA is
marker-dependent, indicating caution is still needed whilst inferring
species abundance based on DNA metabarcoding data when using
PCR-dependent protocols.