Scientists create Black Death family tree

Posted Apr 25, 2014 by Tim Sandle
Scientists have constructed the first view of the Black Death bacterium's entire family tree. The analysis shows how some family members evolve to become harmful.
Archaeologists in Bulgaria found two medieval skeletons pierced through the chest with iron rods to ...
Archaeologists in Bulgaria found two medieval skeletons pierced through the chest with iron rods to supposedly stop them from turning into vampires, preventing them from leaving at midnight and terrorizing the living.
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The study reveals how two bacteria: Yersinia pestis and Yersinia enterocolitica, which are the two major disease-causing species, independently acquired DNA that allowed them to become pathogenic. The researchers found pathogenic members of this bacterial family do not share a recent common disease-causing ancestor, but instead, have followed parallel evolutionary paths to become harmful
The Black Death peaked in Europe between 1348 and 1350, wiping out about 60 percent of London’s population. The Black Death was a pneumonic version of the disease — an airborne infection of the lungs, spread via coughing and sneezing — instead of bubonic — an infection that enters through the skin, infects the lymph system and is spread by rat fleas, according to a science paper by Digital Journalist Tim Sandle.
The latest study into the evolution of the disease causing bacteria is important, for in order to understand how an organism becomes dangerous or pathogenic, scientists need to understand their non-pathogenic family members to see what makes them different to the pathogenic forms.
The researchers found that it was not only the acquisition of genes that has proven important to this family of bacteria, but also the loss of genes seems to be an important trait for the pathogenic species.
The new research has been published in the Proceedings of the National Academy of Sciences, in a paper titled “Parallel independent evolution of pathogenicity within the genus Yersinia.”