A team of researchers creates a huge family tree of 13 million people, spanning 11 generations. The family tree attempts to try and find answers to intriguing questions about the human population.
It has allowed the scientists to dig down into the genealogical history of Europe and North America.
The enormous dataset – slightly higher than the population of Belgium – has provided insight into 500 years of marriage and migration across the Atlantic.
It also allowed the scientists to investigate the role that genes play in influencing human lifespans.
To create the expansive family tree, scientists mined publicly available genealogy data available via a specialised online platform.
“Through the hard work of many genealogists curious about their family history, we crowdsourced an enormous family tree and boom, came up with something unique,” said Professor Yaniv Erlich, the study’s senior author and a computer scientist at Columbia University.
Professor Erlich is also chief science officer at MyHeritage, a genealogy and DNA testing company that owns crowdsourced genealogy website Geni.
For their study, the research team analysed records from 86 million Geni profiles.
They used mathematical graph theory to organise this data and whittle it down to a single tree or “pedigree” of 13 million people spanning an average of 11 generations.
Data within this pedigree mirrored the wider demographics of people who use Geni, with 85 per cent of profiles originating from Europe and North America.
Analysis of this dataset showed historical trends such as the rise in deaths during wars, from the American Civil War to the Second World War, and the reduction in child mortality over the course of the 20th century.
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The researchers also looked at migration patterns, and how these influenced marriages.
Prior to 1750, they found most Americans found their spouses within six miles of their birthplace, but by 1950 this distance had increased to around 60 miles.
They also found that while women in Europe and North America have tended to migrate more than men over the past few centuries, when men have moved they have travelled significantly farther than women.
By incorporating traditional genetic studies into their data, in another part of their study Professor Erlich and his colleagues explored the role genes have played in people’s lifespans over the centuries.
They found that on average, having “good” longevity genes can increase someone’s lifespan by an average of five years.
“That’s not a lot,” said Professor Erlich.
“Previous studies have shown that smoking takes 10 years off of your life. That means some life choices could matter a lot more than genetics.”
Their results were published in the journal Science.
The scientists anticipate their work will provide others with a useful resource when conducting studies of their own.
“We hope that this dataset can be useful to scientists researching a range of other topics,” said Professor Erlich.
“It’s an exciting moment for citizen science,” said Dr Melinda Mills, a demographer at the University of Oxford who was not involved in the study.
“It demonstrates how millions of regular people in the form of genealogy enthusiasts can make a difference to science.”
He added: “The reconstructed pedigrees show that we are all related to each other,” said Professor Peter Visscher, a quantitative geneticist at University of Queensland who was also not involved in the study. “This fact is known from basic population history principles, but what the authors have achieved is still very impressive.”
