NEW YORK (GenomeWeb) – AncestryDNA, the consumer genomics wing of Ancestry.com, continues to upgrade its genetic genealogy service with the rollout of new features.
Earlier this month, the Provo, Utah-based company introduced New Ancestor Discoveries, an expansion of its service that, for the first time in the industry, provides customers with a list of probable ancestors based solely on their microarray data.
This means that customers logging into access their results for the very first time could be provided with the names of individuals who lived as long ago as the 18th century to whom they could be related.
“Using only an individual's genetic data, New Ancestor Discoveries provide to a customer a list of individuals who might be their ancestors — allowing them to get a kick-start in building an otherwise empty family tree,” Julie Granka, population geneticist at AncestryDNA told GenomeWeb via email.
“While genealogy research may eventually be required to position that individual in their family tree, New Ancestor Discoveries are an unprecedented way for an individual to receive hints to their possible ancestors or relatives,” she said.
In the past, users of genetic genealogy services like AncestryDNA would receive a list of other customers whom they matched on certain chromosomal segments. It would then be up to the two customers to compare family trees to identify the potential source of their shared DNA.
Scientists at AncestryDNA were able to expedite this process through the introduction of a new feature called DNA Circles last year. Like New Ancestor Discoveries, DNA Circles relies on customers' genomic data to connect them to a probably common ancestor, typically one who lived during the past two centuries. And not only did DNA Circles pair customers who most likely descended from that individual, but their close relatives, who may not have inherited the same DNA. With New Ancestor Discoveries, clients are provided with a roster of potential ancestors, though it is up to them to determine how they are related to those people.
According to Granka, AncestryDNA has been able to offer these features thanks to its amassed database of array data. Using Illumina microarrays, the company has genotyped more than 800,000 samples since it introduced its AncestryDNA service three years ago. That information, coupled with participants’ online family trees, has enabled AncestryDNA to develop the algorithms that underlie its DNA Circles and New Ancestor Discoveries features.
“The main idea behind New Ancestor Discoveries is that if a customer's DNA matching shows that they are related to a significant number of an ancestor’s descendants in a DNA Circle, they too are likely a descendant – and so should receive a New Ancestor Discovery to this ancestor,” said Granka.
“For every AncestryDNA member, we examine their DNA matching results to every DNA Circle in the database,” she said. “If it looks like they belong to a DNA Circle due to their DNA matching results to individuals in that Circle, they’ll get a New Ancestor Discovery suggesting a possible ancestor or relative who might be part of their family tree.”
According to Granka, AncestryDNA has provided a million New Ancestor Discoveries to 30 percent of its customers since launching the feature earlier this month.
However, while the idea of notifying customers of a likely ancestor, based on their relatedness to other customers who have demonstrated via DNA and records that they share the same common ancestor, may seem like a straightforward approach, there have been some challenges, as all of the people in a particular DNA Circle may originate in, for example, a rural community, and descend from multiple common ancestors. Other customers might also descend from the siblings of a likely common ancestor.
This prompted AncestryDNA to develop methods to overcome these potential roadblocks.
“To provide New Ancestor Discoveries that more often suggest direct-line and collateral-line ancestors, we combined several pieces of information into our algorithm,” Granka noted. These aspects included the number of people in the DNA Circle with whom one shares DNA, the amount of DNA shared with each DNA Circle member, the number of generations back to the ancestor for each individual in the Circle, and the company’s confidence that the customer and each member of the DNA Circle share only one common ancestor.
“These pieces are integrated into a score, with scores above a particular threshold presented to customers as New Ancestor Discoveries,” she said.
As part of AncestryDNA’s research and development, the company ran a number of experiments to assess the algorithm’s performance. “For thousands of individuals from a variety of ethnic backgrounds with deep and full family trees, we took them out of their DNA Circles and calculated their New Ancestor Discoveries,” said Granka. “We found that New Ancestor Discoveries correctly identified ancestors in those individuals’ trees, or was related to the ancestor in another way, about 70 percent of the time.”
The introduction of AncestryDNA’s new feature coincides with a flurry of activity at the genetic genealogy service provider. In January, the company launched expanded its services beyond the US to the UK and Ireland, and, according to company statements, it plans to add Australia and Canada during the remainder of 2015, enabling AncestryDNA to “connect the major English-speaking migrations and globally connect families like never before,” Granka said.
In addition, the firm continues to see demand for its service increase, and in February statement said that it anticipates having a million samples in its database by year end.
This growth, both regional and numerical, should in turn allow more AncestryDNA customers to benefit from the company’s DNA Circles and New Ancestor Discoveries features.
“As AncestryDNA members update their trees and as the AncestryDNA database grows, we will continue to identify new DNA matches and discover additional and larger DNA Circles, resulting in new opportunities for additional New Ancestor Discoveries,” Said Granka. “The most exciting part about New Ancestor Discoveries is that their impact can only increase over time,” she added, “bringing the power of DNA matching integrated with family trees to even more AncestryDNA members with diverse and complex family histories.”