The Valley of Forgetting: Alzheimer's Families and the Search for a Cure by Jennie Erin Smith

 

"The simplest explanation, he said, was that Colombia, during the Spanish Conquest, saw a cornucopia of rare mutations from African, European, and Indigenous sources. It also suffered, during that same period, a number of genetic bottlenecks. In a bottleneck, a population shrinks due to some disaster—disease, war, genocide, or famine—leaving the surviving population with reduced genetic variation. If and when that population bounces back, rate variants that made it through the bottleneck are overrepresented."