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Jennifer A. Doudna studies RNA–protein systems and their roles in gene expression. She coauthored the 2011 Xrn1 study with Martin Jinek and Scott M. Coyle, connecting recognition of an RNA's $5^{\prime }$ end with its processive degradation.^[ref]

Doudna also coauthored the 2012 biochemical demonstration that Cas9 uses RNA guides for sequence-directed DNA cleavage. The study showed that a single engineered RNA could combine the guiding functions of the natural two-RNA system, establishing a basis for programmable CRISPR genome editing.^[ref]

The distinction between cutting a molecule and editing a genome is essential. Cleavage is an experimentally observed chemical event; the final inherited sequence additionally depends on DNA repair and cellular context. A nuclease result alone does not specify a repaired allele.

For an original geometric example, one complete double-strand cut in a circular DNA molecule opens it into one linear molecule. One internal double-strand cut in an already linear molecule instead gives two fragments. The same number of cuts can therefore yield different product counts depending on the starting topology. This elementary accounting illustrates why a gel electrophoresis result must be interpreted with a known starting substrate; it is not a numerical result from either paper.

Scott M. Coyle coauthored a 2011 biochemical and structural investigation of Xrn1 with Martin Jinek and Jennifer A. Doudna. It linked Xrn1 5′-phosphate recognition with processivity, the persistence of successive cleavage events during an enzyme–substrate encounter.^[ref]

The experimental evidence included degradation of labeled RNA assessed by polyacrylamide gel electrophoresis. Comparing intact substrate with shorter products helped distinguish efficient complete processing from the accumulation of intermediates.^[ref]

An original bookkeeping example separates molecule disappearance from the number of cleaved bonds. Suppose a sample begins with $100$ identical chains, each $20$ nucleotides long. If every chain loses just one terminal nucleotide, none of the original full-length molecules remains, but $100\times 19=1900$ nucleotides are still present in the shortened chains. Their loss from the full-length band does not imply complete conversion into individual nucleotides.

Conversely, a large amount of short product at one sampling time does not alone measure the reaction rate or prove that each chain stayed bound throughout processing. A time series and appropriate controls add information that a single end-point gel electrophoresis image cannot supply. These are interpretive examples, without an inferred assignment of individual experiments from Coyle's author position.