Perhaps you’ve used sites like Ancestry to construct your own family tree, looking back in time to find out how your relationships came to be. All family trees tell a story. In the pre-internet era, this work involved hunting through microfiche and birth, death and immigration records. Now a fascinating global story has emerged Science: the largest family tree ever created. Genealogical mapping by scientists at the University of Oxford and the Broad Institute of MIT and Harvard University has produced a tree of 27 million ancestors that traces human evolution and migration back a million years.
The project is born of the great advances in DNA sequencing and big data computing in recent decades. Researchers took genome data from 3,609 modern and ancient people across 215 populations. Some of these samples are up to 100,000 years old. This massive data required an extremely innovative algorithm by the Big Data Institute at the University of Oxford. The algorithm notes genetic variations and hypothesizes backwards to trace where they came from as the genome evolved and ancient humans moved places. The end result maps 27 million ancestors.
Anthony Wilder Wohns, a postdoc at MIT who led the study, emphasized the importance of the map in a statement. “Essentially, we reconstruct the genomes of our ancestors and use them to form a large network of relationships. We can then estimate when and where these ancestors lived. The strength of our approach is that it makes very few assumptions about the underlying data and may also include both modern and ancient DNA samples.”
He told Reuters: “The earliest ancestors we identify trace back in time to a geographic location in modern Sudan. These ancestors lived up to and over 1 million years ago – which is much older than current estimates for the age of Homo sapiens – 250,000 to 300,000 years ago. So parts of our genome have been inherited from individuals that we wouldn’t recognize as modern humans.”
Yan Wong, an evolutionary geneticist at the Big Data Institute and a lead author of the study, noted: “We’ve basically built a huge family tree, a genealogy for all of humanity, modeling as accurately as we can the history that generated all the genetic variation we found in humans today. This genealogy allows us to see how each person’s genetic sequence relates to each other, along all points in the genome.”
Such algorithms could be used to chart the evolution of other species, including plants and animals. Accuracy will improve as the technology does, and the team hopes to continue updating the tree as genomes can be added. While some finds of the tree are still unsupported by archaeological evidence, it underscores the ways in which traditional historical approaches and cutting-edge science can combine to enrich human history.
Through genealogical mapping and big data, scientists have created a visualization of human genetics and migration in the largest family tree ever created.
It includes 27 million ancestors and goes back a million years.
h/t: (Smithsonian Magazine)
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