Scientists have identified the pathogen that caused the potato blight of 1845, one of the factors which led to the countries devastating Great Hunger, killing one million people.

The DNA extracted from 19th Century samples showed that this strain, HERB-1, which caused so much death in the 1800s, is different from modern day epidemics which continue to attack crops around the world.

A team led by The Sainsbury Laboratory, Norwich, traced the spread of the potato blight from the 1800s to present day. Until now it was unknown how the blight, Phytophthora infestans, was related to those of today.

The study, published in the journal eLife, shows that the strain HERB-1 is likely to have been linked to a fungal disease which came to Ireland from Mexico.

Between 1846 and 1851 one eighth of Ireland’s population were killed while another two million emigrated. The potato blight, along with the actions and inactions of the British Government at the time, were catastrophic.

Scientists in the United Kingdom, Germany, and the United States analyzed dried leaves from Kew Royal Botanical Gardens, UK, and Botanische Staatssammlung Munchen, Germany, the BBC report.

Prof Sophien Kamoun of The Sainsbury Laboratory said, “This strain was different from all the modern strains that we analyzed - most likely it is new to science.

"We can't be sure but most likely it's gone extinct."

A depiction of a family during The Great HungerGoogle Images