― Dr. Melba Ketchum's DNA Diagnostics Better Business rating is an "F"Disappointed by the delay in the Bigfoot DNA results? Get in line. A Post by Michael Merchant of the Team Tazer Bigfoot Fanpage linked to the Better Business Bureau® rating for Dr. Melba Ketchum's business DNA Diagnostics, Inc. Unfortunately on a scale from A-F, Melba's company gets an F. Why? Failure to deliver DNA Results. In these cases it is Horse, Cat and Dog DNA results. ∙ Under the additional complaint information [...].