How genome reconstruction pieces together Black Death puzzle
Scientists in Canada, Germany and the United States have succeeded in reconstructing the ancient genome of Yersinia pestis, the bacterium responsible for the infamous Black Death, a devastating pandemic that peaked in Europe in the mid 14th century. Presented in the journal Nature, the result of this groundbreaking study could help shed light on the mechanisms of pathogen evolution and adaptation for emerging and re-emerging infections. Researchers could use this novel information to improve their knowledge of modern infectious diseases. Led by the University of Tübingen in Germany and McMaster University in Canada, this study is the first ever to draft a reconstructed genome of any ancient pathogen. The scientific team included experts from the Max Planck Institute for Evolutionary Anthropology in Germany and the University of South Carolina in the United States. The researchers presented a new methodological approach to pull out tiny degraded deoxyribonucleic acid (DNA) fragments of the causative agent of the Black Death. Once they demonstrated how a specific variant of the Yersinia pestis bacterium was behind the plague that resulted in the death of 50 million Europeans between 1347 and 1351, the team then targeted the 'capture' and sequencing of the entire genome. 'The genomic data show that this bacterial strain, or variant, is the ancestor of all modern plagues we have today worldwide,' explains Professor Hendrik Poinar, a geneticist at McMaster University and one of the paper's authors. 'Every outbreak across the globe today stems from a descendant of the medieval plague. With a better understanding of the evolution of this deadly pathogen, we are entering a new era of research into infectious disease.' Commenting on the result of the study, senior author Johannes Krause from the Institute for Archaeological Sciences and the Human Genetics Department at the University of Tübingen says: 'Using the same methodology, it should now be possible to study the genomes of all sorts of historic pathogens. This will provide us with direct insights into the evolution of human pathogens and historical pandemics.' The researchers say the direct descendants of the same bubonic plague are still present today and responsible for the death of around 2,000 people each year. 'We found that in 660 years of evolution as a human pathogen, there have been relatively few changes in the genome of the ancient organism, but those changes, however small, may or may not account for the noted increased virulence of the bug that ravaged Europe,' Professor Poinar says. 'The next step is to determine why this was so deadly.' Thanks to sophisticated techniques in the recovery and sequencing of DNA, scientists have been able to significantly expand the scope of genetic analysis of ancient specimens. Members of the team evaluated the skeletal remains from victims buried in the East Smithfield 'plague pits' in London, United Kingdom, or what is currently known as the Royal Mint. The researchers extracted, purified and enriched specifically for the pathogen's DNA. In effect, they decreased the background DNA consisting of human, fungal and other non-plague DNA to focus their examination of the pathogen. Both Canadian and German funding bodies supported this study.For more information, please visit:Nature:http://www.nature.com/University of Tübingen:http://www.uni-tuebingen.de/en/landingpage.htmlMcMaster University:http://www.mcmaster.ca/
Countries
Canada, Germany, United States
