Published: 13 June 2013

Unravelling 1,000 year old DNA to unlock the history of leprosy

Molecular microbiologists from the University of Surrey have broken new ground to advance the understanding of leprosy.

Working in collaboration with a team of archaeologists from the University of Winchester, Surrey academics — including Professor Graham Stewart, Dr Tom Mendum, HuiHai Wu and Dr Mike Taylor — extracted DNA from skeletal samples buried at the medieval St Mary Magdalen Hill leprosy hospital in Winchester. Read more in the journal PlosOne.

Because the ancient DNA was so well-preserved, the team was able to reconstruct the entire genome of the ancient leprosy bacterium, shedding light on the history of the disfiguring disease - once endemic in Europe but which largely disappeared during the Middle Ages. The team believes the waxy coat surrounding the leprosy bacterium may have protected the DNA from degradation.

Professor Stewart, acting head of the Department of Microbial and Cellular Sciences, said: “Understanding diseases from the past will help us predict emerging infectious diseases and potentially suggest how we may be better able to control existing diseases. We hope to analyse even older DNA, tracing leprosy and also tuberculosis back to their origins in human history.”

The research was published in the journal Science, as part of an international project to reconstruct genome sequences of bacteria from five medieval skeletons excavated in Denmark and Sweden, as well as the United Kingdom. The research compared the ancient genomes with those of 11 modern strains of leprosy from around the world and revealed that leprosy in the Americas has a European origin, and that particular leprosy strains now found exclusively in the Middle East were at one time also present in Europe.

Bioarchaeologist Dr Taylor said: “The excavations at St. Mary Magdalen, Winchester and other European sites bring us literally face-to-face with the effects the disease had on susceptible people, almost a millennium before the advent of antibiotics”.

The site of the St Mary Magdalen Hill leprosy hospital in Winchester has previously featured on the Channel 4 TV show Time Team. Watch the show on 40D

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