World record family tree links 27 million people

It’s the grand sequoia of family trees.

Researchers at the University of Oxford’s Big Data Institute have created the largest-ever family tree, which links more than 27 million people — both living and long dead — across the world.

This marks a major milestone in the journey toward mapping the entirety of human genetic relationships, per the groundbreaking study, published in Science.

The family tree helps us know more about where and when our human ancestors lived — namely in Africa — the researchers said.

It also could predict who might be more susceptible to diseases such as COVID-19.

“We have basically built a huge family tree, a genealogy for all of humanity, that models as exactly as we can the history that generated all the genetic variation we find in humans today,” co-author Yan Wong, an evolutionary geneticist at the institute, said in a statement. “This genealogy allows us to see how every person’s genetic sequence relates to every other, along all the points of the genome.”

In layperson’s terms, the comprehensive tree, which appeared as both a research paper and a video, depicts how people around the world are interrelated, like an all-encompassing 23andMe.

Until now, genetic cartographers had struggled with devising algorithms to process these massive amounts of data. However, through the new method detailed in the study, researchers can easily match data from multiple sources and incorporate millions of genetic sequences.

“Essentially, we are reconstructing the genomes of our ancestors and using them to form a vast network of relationships,” explained lead author Anthony Wilder Wohns, who took on the research as part of his Ph.D. at the BDI. “We can then estimate when and where these ancestors lived.”

He added, “The power of our approach is that it makes very few assumptions about the underlying data, and can also include both modern and ancient DNA samples.”

“While humans are the focus of this study, the method is valid for most living things, from orangutans to bacteria,” explained author Anthony Wilder Wohns.
Courtesy of Science

Specifically, the study mix-and-matched data from both modern and ancient human genomes from eight different databases, spanning a total of 3,609 individual genome sequences from 215 populations across the world. The ancient genomes ranged in age from 1,000 to over 100,000, while “the resulting network contained almost 27 million ancestors.”

Per the study, the algorithms “predicted where common ancestors must be present in the evolutionary trees to explain the patterns of genetic variation.”

The map also employed location data, allowing scientists to estimate where the common ancestors had lived, and included seminal evolutionary events such as our migration out of Africa, per the study. The earliest ancestors included in the map are an extinct species of human that predates Homo sapiens. They lived a million years ago in a region estimated to be modern Sudan.

While undeniably impressive, the unprecedented family tree is just the foundation “for the next generation of DNA sequencing,” Wong said. The genome scientists are currently working on making the blueprint even more comprehensive by “continuing to incorporate genetic data as it becomes available.”

Their ultimate goal: To produce an all-encompassing map of how everyone around the globe is related to each other.

“As the quality of genome sequences from modern and ancient DNA samples improves, the trees will become even more accurate, and we will eventually be able to generate a single, unified map that explains the descent of all the human genetic variation we see today, Wong said.

The map isn’t just applicable to humans.

“While humans are the focus of this study, the method is valid for most living things, from orangutans to bacteria,” Wohns explained. In other words, it could potentially literally describe which monkey was your uncle.

In a similar, more pressing study from 2020, scientists at the New York City Department of Health and Mental Hygiene analyzed the coronavirus’ genetic material to try and predict the origins of future outbreaks.

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