A red dot on a cave wall in Portugal does not look like much. It’s a small mark, crusted over by minerals, easy to miss ...
An international team of cave explorers has shown that cave walls and the prehistoric rock art that adorns them can preserve human DNA for thousands of years.
Contamination and other errors in DNA analysis have occurred at the Washington State Patrol crime labs, most of it the result of sloppy work. The most common problems are cross-contamination by ...