Human DNA Contamination Seen in Genome Databases

 Nearly 20 percent of the nonhuman genomes held in computer databases are contaminated with human DNA, presumably from the researchers who prepared the samples, say scientists who chanced upon the finding while looking for a human virus. The problem it contamination raised are: 1. contamination of human samples by other human DNA is very hard to distinguish from normal variation, and could lead to erroneous medical decisions. 2.Most DNA sequencing now uses a fast, cheap technology that matches fragments of DNA to the reference genomes already in the databanks, assuming they are fully accurate. This method, called resequencing, gives the computer assembly algorithms much less chance of catching contamination.
Dr. O’Neill, researcher at University of Connecticut, said:“I’m nervous that this paper will make some people unhappy, and I’m also nervous that some people won’t pay attention to it.”