Columbia University researchers have identified a huge family tree spanning 11 generations based on data from a collaborative genealogy website. This is the largest single-family tree established so far. With 13 million people under its canopy, it is of the order of the population of Bengaluru. Though the researchers would need to go back 65 generations further to get the whole tree and converge on a single ancestor, the existing data is good enough to indicate some factors. By comparing each individual’s lifespan to that of their relatives, and looking at their degree of separation, they find that good longevity genes can extend a person’s lifespan by just 5%, indicating the slight role of genes in affecting lifespan.