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Teemu Kivioja led work on counting original nucleic-acid molecules using unique molecular identifiers. A sequence label attached before amplification lets descendants of one starting molecule be recognized, so repeated reads from that molecule need not be mistaken for many independent originals.^[ref]

For example, a hundred reads with one valid molecular identifier can represent one amplified starting molecule, whereas a hundred different valid identifiers can represent many originals. Identifier collisions and sequencing errors complicate that idealization. The contribution links molecular population measurement to an explicit observation model, separating amplification yield from original molecular abundance.