 Further study  revealed that the three enzymes that the bacteria were using to digest the byproducts were significantly different from any other enzymes produced by any other bacteria, and not effective on any material other than the manmade nylon byproducts.This discovery led geneticist Susumu Ohno to speculate (in a paper published in April 1984) that the gene for one of the enzymes, 6-aminohexanoic acid hydrolase, had come about from the combination of a gene-duplication event with a frameshift mutation.Ohno suggested as a likely cause the insertion of thymine.