The New York Times reports that it is possible to fabricate blood and saliva samples containing DNA from a person other than the donor, and even to construct a sample of DNA to match someone's profile without obtaining any tissue from that person — if you have access to their DNA profile in a database. This undermines the credibility of what has been considered the gold standard of proof in criminal cases. I am not yet sure what it means to DNA evidence in genealogy.
"You can just engineer a crime scene," said Dan Frumkin, lead author of the paper. "Any biology undergraduate could perform this."
Tania Simoncelli, science adviser to the American Civil Liberties Union, says the findings were worrisome. "DNA is a lot easier to plant at a crime scene than fingerprints," says Simoncelli. "We're creating a criminal justice system that is increasingly relying on this technology."
The New York Times article is at http://www.nytimes.com/2009/08/18/science/18dna.html although a subscriber's user name and password is required to access that web page.