This is terrible news. I am not sure I grasp the mechanism by which unexpected DNA, from animals uninvolved in the research gets into the produced genomes, but E.coli was mentioned as the culprit, which makes me think bacterial lateral gene transfer is the mechanism. This should be relatively trivial to sort, now that it's known to impact this research.

No one, particularly not researchers intent on particular results, wants unexpected DNA to adulterate their products.

Thanks!