One million people are thought to have died during the devastating famine (Image: Getty)
Scientists have discovered new evidence that the pathogen that caused the potato famine may have originated thousands of miles away.
A study that examined the DNA of Phytophthora (P.) infestans, and similar species has pointed the finger at the Andes Mountains.
The pathogen is thought to have spread from South America to North America before wreaking havoc in Ireland in the 1840s.
Also known as the Great Hunger, the devastating blight that affected crops is estimated to have killed around one million people between 1845 and 1849.
Study author Professor Jean Ristaino, an expert in plant pathology at North Carolina State University, said: “It’s one of the largest whole-genome studies of not only P. infestans, but also the sister lineages.
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“By sequencing these genomes and accounting for evolutionary relationships and migration patterns, we show that the whole Andean region is a hot spot for speciation, or where a species splits into two or more distinct species.”
Experts have been split over theories about the origin of the pathogen, with some arguing that was a more likely location.
But the new paper identified distinct differences between P. infestans and the two Mexican pathogen species.
The pathogen still causes late-blight disease on potato and tomato plants around the world.
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Prof Ristaino said efforts to breed more resistant lines of potatoes should focus more on the Andes.
She added: “ is bringing more drought to higher Andean elevations, so we could be losing some of these potatoes before we learn if they could provide resistance to late-blight disease.”
The findings were published in the journal PLOS One.