Deadly Black Death bug hasn't changed, but we have

Undated handout image provided by Rocky Mountain Laboratories showing an electron micrograph depicting a mass of Yersinia pestis bacteria (the cause of bubonic plague). (AP Photo/Rocky Mountain Laboratories)

October 14, 2011 9:54:10 AM PDT
Scientists have cracked the genetic code of the Black Death, one of history's worst plagues, and found that its modern day bacterial descendants haven't changed much over 600 years.