Scientists used modern genetic sequencing and rotten old museum samples to peer back in time at the cause of the potato blight that led to more than 1 million deaths in Ireland in the 1840s.
The fungus-like water mold that ravaged the country's potato crop sent hungry Irish survivors fleeing for far-flung new countries -- which is why so many people now justify getting wasted every St. Patrick's Day, saying they're sure they have an Irish ancestor somewhere in their family tree.
What the scientists found was a strain of Phytophthora infestans that is different from similar water molds that are still ravaging the world's crops. From the BBC:
Researchers in the UK, Germany and the US analysed dried leaves kept in collections in museums at Kew Royal Botanical Gardens, UK, and Botanische Staatssammlung Munchen, Germany.