Great Irish Potato Famine and Phytophthora Infestans

Great Irish Potato Famine and Phytophthora Infestans: A new study has found that pathogen responsible for the Great Irish Potato Famine that killed thousands evolved thousands of miles away from the Emerald Isle, in the Andes mountain range of South America.

• About: A pathogen is a microorganism, virus, toxin, or ionizing radiation that causes disease. Pathogens can affect humans, animals, plants, and other microorganisms.
• Key Finding:

o The Great Irish Potato Famine (1840s) was caused by Phytophthora infestans.

o Originated in the Andes Mountains, South America, not Ireland.

o Still causes late blight in tomatoes and potatoes worldwide.

• Migration Patterns

o P. infestans spread from South America to North America, then to Ireland.

o Data shows more migrations into and out of South America compared to Mexico.

o Gene flow occurred between the Andes and Mexico, both historically and recently.

• Trade Influence: Modern global trade mixes pathogen populations in South America and Mexico.