However, some people who have early-onset Alzheimer's don't have mutations in these three genes. That suggests that this early-onset form of Alzheimer's disease is linked to other genetic mutations that haven't been identified yet.
Early history Cigars, cigarettes Cancer by the carton Legal history Surgeon General's warning. (CNN) -- Tobacco was first used by the peoples of the pre-Columbian Americas. Native Americans apparently cultivated the plant and smoked it in pipes for medicinal and ceremonial purposes.
By experimenting with growing and curing tobacco from seeds obtained from the Caribbean, John Rolfe developed the colony's first profitable export. Before 1611, Rolfe began cultivating tobacco seeds grown in the West Indies; he probably obtained them from Trinidad or some other Caribbean location.