SCIENTISTS have used 19th century plant samples to uncover the cause of the Great Famine in Ireland.
The newly discovered pathogen is believed to have triggered the potato blight that spread through Ireland from 1845.
In the following decade, as people around the country discovered that their staple food had been turned into an inedible mush, one million people died from starvation and disease while two million were forced into exile.
More than 150 years later, the Irish population remains at three-quarters of pre-famine levels.
It had long been known that the fungus-like infection Phytophthora infestans was behind an Gorta Mór.
But only by consulting potato plant leaves as old as 170-years could a team of molecular biologists from Europe and the US, led by The Sainsbury Laboratory in Norwich, discover the real cause.
Using high-tech methods of DNA sequencing, they were able to pinpoint the exact structure of the pathogen’s DNA.
The scientists concluded that the strain, called HERB-1, is different to the culprits of contemporary blights and is now extinct.
Samples used in the study, published in the open-access scientific journal eLife, came from Ireland, Britain, Europe and North America and had been preserved in London’s Kew Gardens as well as the Botanical State Collection in Munich.
The scientists now believe that their research can open new avenues of research into the evolution of pathogens and how human activity impacts the spread of disease.
“What is for certain is that these findings will greatly help us to understand the dynamics of emerging pathogens,” said Kentaro Yoshida from The Sainsbury Laboratory.
“This type of work paves the way for the discovery of many more treasures of knowledge hidden in herbaria.”