The lack of genetic variation in the Irish potatoe (the Lumper potatoe) contributed to the catastrophe. Given that the country held big areas of monoculture of this tubercle and a huge amount of people depended on it to feed themselves, their families and the livestock, when a fungus stroke, causing the "potato blight" and the loss of three consecutive crops, millions perished from famine and diseases such as cholera and typhus.
People fled from the country in ships for the United States, Great Britain and even Canada, but many perished in the way. Others were also never able to come back home again, because of the poverty they lived in in the new countries. Such sad time is remembered until today by the Irish folk, in monuments such as the Memorial in Dublin.