With popular genetic testing company 23andMe filing for bankruptcy, what does the future of ancestry DNA look like?
A team of researchers from the University of Michigan says it is going to look more like a movie than a portrait, thanks to a new statistical model that can be used to trace ancestry in a new way.
Redefining the Family Tree
This new statistical method, developed by Gideon Bradburd and fellow University of Michigan (U-M) researchers Michael Grundler and Jonathan Terhorst, promises to give a more complete picture of human ancestry. The team refers to this as a movie version of ancestry, which provides not only your genetic makeup but where your ancestors originated and how they moved to get where they are today.
The statistical method, called Gaia (geographic ancestry inference algorithm), combines modern genetic sequencing with ancient DNA techniques to craft a nuanced and unique portrait of ancestral connections.
At the beginning of the process, researchers start with a simple assumption: that when people move, they often move locally. Gaia then takes this assumption and merges it with both modern locations and genetic structure to create a dynamic picture of ancestry.
This new modern method, published in Science, traces back to Nobel Prize- winning geneticist Svante Pääbo and his work in ancient DNA. Pääbo developed the groundbreaking tools that make genotyping ancient DNA possible.
Thanks to these tools, the team from U-M was able to trace the spread of human populations and to see how these populations entered and left specific geographic areas at specific points in time. By using modern genetic sequencing alongside population tracking and movements, Gaia can provide a comprehensive family tree that extends over centuries.
Read More: Ancient DNA Unlocks Missing Link in the Origin Story of Indo-European Language
Tracing Ancestry
This new model of ancestry tracing differs greatly from the common methods employed by many popular companies. In comparison to the type of report Gaia can create, the typical personalized ancestry report’s scope is incredibly small and only provides a snapshot of a family tree from a particular place and time.
Often, when you receive an ancestry report, you are provided with a percentage calculation revealing something like you are 50 percent Irish. What this actually means is that you likely have a lot of current relatives, like second or fourth cousins, currently living in Ireland.
According to the U-M research team, your family tree is much more active than this static result, and so is the family tree of all humans.
“Because our pedigrees explode so quickly, they also must collapse in the same sense that you and I must share many, many relatives at many points back in time, and that’s true for every person alive on Earth,” said Bradburd in a press release. “We’re all extraordinarily closely related to each other.”
The Future of Population Genetics
Gaia was created partially in response to a call from the National Academy of Sciences asking the field of human population genetics to move away from race-based labels.
When it comes to population genetics, racial categories and labels are archaic and often imprecise, leading to inaccurate predictions about genetic variation. This is because sharing a racial category or label does not mean that two people are genetically or ancestrally similar.
A model like Gaia can help rectify this problem by highlighting how much genetics can shift over time in a certain geographic region.
This new method can also be used in areas beyond human genetics, including tracking the emergence of viruses, the divergence of animal populations, and other genealogical tracking.
Currently, the research team at U-M is collaborating with scientists across the globe. Researchers in Australia are using Gaia to learn how mosquitoes colonized islands in the South Pacific, while teams in Michigan and Ohio are using it to understand the history and dispersal of the Massasauga rattlesnake.
Read More: DNA Ancestry Tests Can Expose Family Secrets
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