Nothing like a plague and death to draw a little interest on a Sunday morning!
This comparison of the genome of Yersinia pestis - the bacteria responsible for causing the Black Death - from samples taken from corpses uncovered recently in London, with modern day samples of the same bacterium shows that the 2 bacterium have pretty much identical genomes. What does this tell us? Well, if you think back to your school days, you may remember being taught that it was rats that transmitted this lethal bacteria (or rather their fleas), and it was assumed that the bacterium responsible for this disease was a lot more aggressive than its modern day counterpart. The finding that the DNA of both the old type of Yersinia pestis, and the modern day version are pretty much the same, tells us 2 things - that the version of Yersinia pestis responsible for the Black Death was no more aggressive than its modern day counterpart, and that rats (or their fleas) couldn't have been responsible for the spread - for the black death to have achieved the epic amount of infection that it did, it would have to have spread faster than transmission by rodents - it had to have been airborne.
Amazing what we can find when we look at a little DNA!
By extracting the DNA of the disease bacterium, Yersinia pestis, from the largest teeth in some of the skulls retrieved from the square, the scientists were able to compare the strain of bubonic plague preserved there with that which was recently responsible for killing 60 people in Madagascar. To their surprise, the 14th-century strain, the cause of the most lethal catastrophe in recorded history, was no more virulent than today's disease. The DNA codes were an almost perfect match.