Caption: A 6,000-person family tree, showing individuals spanning seven generations (green) and their marital links (red). Credit: Columbia University, New York City
You may have worked on constructing your family tree, perhaps listing your ancestry back to your great-grandparents. Or with so many public records now available online, you may have even uncovered enough information to discover some unexpected long-lost relatives. Or maybe you’ve even submitted a DNA sample to one of the commercial sources to see what you could learn about your ancestry. But just how big can a family tree grow using today’s genealogical tools?
A recent paper offers a truly eye-opening answer. With permission to download the publicly available, online profiles of 86 million genealogy hobbyists, most of European descent, the researchers assembled more than 5 million family trees. The largest totaled more than 13 million people! By merging each tree from the crowd-sourced and public data, including the relatively modest 6,000-person seedling shown above, the researchers were able to go back 11 generations on average to the 15th century and the days of Christopher Columbus. Doubly exciting, these large datasets offer a powerful new resource to study human health, having already provided some novel insights into our family structures, genes, and longevity.
While attending college in her native Colombia, Yakeel T. Quiroz joined the Grupo de Neurociencias de Antioquia. This dedicated group of Colombian researchers, healthcare workers, and students has worked for many years with a large extended family in the northwestern district of Antioquia that is truly unique. About half of the more than 5,000 family members inherit a gene mutation that predisposes them to what is known locally as “la bobera,” or “the foolishness,” a devastating form of early-onset Alzheimer’s disease. Those born with the mutation are cognitively healthy through their 20s, become forgetful in their 30s, and descend into full-blown Alzheimer’s disease by their mid-to- late 40s. Making matters worse, multiple family members sometimes are in different stages of dementia at the same time, including the caregiver attempting to hold the household together.
Quiroz, now a researcher at Massachusetts General Hospital in Boston, vowed never to forget these families. She hasn’t, working hard to understand early-onset Alzheimer’s disease and helping to establish the Forget Me Not Initiative to raise money for affected families. With an NIH Director’s Early Independence Award, Quiroz also recently launched her own lab to pursue an even broader scientific opportunity: discover subtle pre-symptomatic changes in the brain years before they give rise to detectable Alzheimer’s. What she learns will have application not only to detect and possibly treat early-onset Alzheimer’s in Colombia but also to understand the late-onset forms of the dementia that affect an estimated 35.6 million people worldwide.