A research group wrote to us with sequencing from three aptamer selections. All three had enriched. None had resolved into anything they could confidently order. This is what we did with it.
Three campaigns against different targets, all built on the same starting library, sequenced at two rounds each. The pools had clearly enriched. What the group could not do was turn that into a decision: which molecules to synthesise, in what order, and on what grounds.
This is the ordinary failure mode of a selection that succeeded. Abundance ranking hands you the winner and tells you nothing about why it won, whether it is one molecule or one molecule's sequencing noise, or whether the runner-up is a genuine alternative or an artefact. The gap is not in the wet lab. It is in the analysis.
Family sheets went back the same day — together with a correction to one of the construct parameters the group had given us.
Delivered more than three weeks ahead of the deadline they had set us.
Within three days of first delivery the group committed every remaining dataset, and invited us to co-author the resulting publication.
All three targets in one analysis: body, per-target annexes, a chain-by-chain appendix, and a machine-readable table of every family member.
Construct parameters are checked against the data, not taken from the brief. Here the brief was wrong — and every downstream figure would have inherited the error.
Which read is the aptamer and which its complement, derived from the selection chemistry and confirmed independently. Not assumed from how the files were named.
Agreement between the two reads of a pair is a stricter test than any quality-score threshold, and it costs nothing.
A dominant molecule surrounded by its own sequencing variants otherwise reads as a family of ten. Collapse first, and every chain in a family is a different molecule.
One is the unit you order synthesis against; the other is the unit a biological argument rests on. Conflating them inflates both.
A fold-enrichment is only as good as its denominator. We use the complete singleton fraction of the earliest rounds, and state the choice so the figures can be recomputed rather than believed.
A handful of chains sharing a rare element gives a spectacular ratio and almost no evidence. Every reported family survives a test corrected for the whole search.
Base-pairing partners are resolved computationally. Reading a dot-bracket string by eye is how confident structural claims turn out to be wrong.
Index bleed-through between multiplexed samples was found, measured and identified as an artefact — before it could be read as a biological result.
A report a client cannot audit is one they have to take on faith — the wrong basis for spending a synthesis budget.
Nothing in a deliverable like this has been shown to bind. Selection sequencing produces a priority order for synthesis and testing — not affinities, not specificity, and not a validated binder. We say so in every report, because the alternative is a client spending months discovering it.