Reading your DNA barcoding report: a guide for non-scientists

You've just received your barcoding report and it's full of numbers, percentages, and Latin names. Here's what it all means.

The headline: species identification

The big name at the top is our best determination of what your specimen is. If we write Trametes versicolor with 'high confidence', that means the molecular evidence strongly supports this identification.

Identity percentage

This is the most important number. It tells you how similar your sequence is to the closest match in the reference database. Here's how to interpret it:

≥99% — Almost certainly the same species. Especially if the match is to a 'type specimen' (the officially designated reference specimen for that species name).

97-99% — Likely the same species, or a very closely related one. Some species complexes (groups of nearly identical species) fall in this range.

95-97% — Probably the same genus, but possibly a different species. The sequence might represent an undescribed species.

<95% — Either a more distant relationship, or the sequence quality might be low. We'll note this in the report.

Query coverage

This tells you what percentage of your sequence aligned to the database match. You want this above 80%. If it's low, it might mean the sequence was short or had quality issues at one end.

The chromatogram

Those coloured peaks are the raw data from the sequencing machine. Each peak represents one DNA base: A (green), C (blue), G (black), T (red). Clean, evenly spaced, single peaks mean a high-quality read. Double peaks at the same position suggest contamination (two different organisms in the sample).

The phylogenetic tree

This shows where your organism sits on the tree of life relative to its closest relatives. The branch lengths represent evolutionary distance — longer branches mean more genetic divergence. Your specimen is marked with a star.