Data from: Minimizing polymerase biases in metabarcoding

DNA metabarcoding is an increasingly popular method to characterize and
quantify biodiversity in environmental samples. Metabarcoding approaches
simultaneously amplify a short, variable genomic region, or “barcode”,
from a broad taxonomic group via the polymerase chain reaction (PCR),
using universal primers that anneal to flanking conserved regions. Results
of these experiments are reported as occurrence data, which provide a list
of taxa amplified from the sample, or relative abundance data, which
measure the relative contribution of each taxon to the overall composition
of amplified product. The accuracy of both occurrence and relative
abundance estimates can be affected by a variety of biological and
technical biases. For example, taxa with larger biomass may be better
represented in environmental samples than those with smaller biomass.
Here, we explore how polymerase choice, a potential source of technical
bias, might influence results in metabarcoding experiments. We compared
potential biases of six commercially available polymerases using a
combination of mixtures of amplifiable synthetic sequences and real
sedimentary DNA extracts. We find that polymerase choice can affect both
occurrence and relative abundance estimates, and that the main source of
this bias appears to be polymerase preference for sequences with specific
GC contents. We further recommend an experimental approach for
metabarcoding based on results of our synthetic experiments.