Without such data it is impossible to rule out the possibility that the ancient Australian sequences result from modern human contamination of the bone during handling over the years, complicated by DNA damage. (talkorigins.org)
They also found significant human contamination immediately after a weekend jazz festival, whereas testing by conventional methods yielded a much weaker signal after a time lag of a couple days. (sciencedaily.com)
In order to prevent human contamination, it is important to wash hands frequently after handling felines. (hartzflea.com)