Zee Media Bureau
New Delhi: After 160 years, scientists have finally identified the strain of potato blight that caused the Irish potato famine which ravaged Ireland from 1845 to 1852, killing one million people.
A team of international molecular biologists sequenced the genomes of Phytophthora infestans and its host - the potato, from samples preserved at the Botanische Staatssammlung Munchen, Germany and the Kew Gardens in London.
“The degree of DNA preservation in the herbarium samples really surprised us,” said study co-author Johannes Krause, a professor of paleogenetics at the University of Tübingen in Germany.
Scientists believe the strain, named HERB-1, may have originated in Toluca Valley, Mexico and spread from there in the early 1800s.
“We have finally discovered the identity of the exact strain that caused all this havoc,” Hernán Burbano, a co-author and a researcher at the Max Planck Institute for Developmental Biology in Germany said.
HERB-1 was replaced by another Phytophthora infestans strain, US-1, after new potato varieties were introduced in the twentieth century.
The study shows that the evolution of pathogens is affected by crop breeding methods.
"Perhaps this strain became extinct when the first resistant potato varieties were bred at the beginning of the 20th century," Kentaro Yoshida, lead author and a researcher at The Sainsbury Laboratory in the United Kingdom, said. "What is for certain is that these findings will greatly help us to understand the dynamics of emerging pathogens."