The Human Genome Project, which mapped out the complete human genome—three billion nucleotides—took 13 years to complete and cost $3-billion. According to Wikipedia, to do it they used “the selective incorporation of chain-terminating dideoxynucleotides by DNA polymerase during in vitro DNA replication.” (The what?!)
A dozen years has made things simpler, faster, and cheaper. Genetic genealogy testing technology now resides within a microchip. According to the International Society of Genetic Genealogy, the big genealogy DNA testing companies all use some form of a chip (pictured to the right) made by Illumina. Illumina says the chip can complete thousands of samples a week, up from one every 13 years. The chip looks at an economical 700,000 of the three billion nucleotides.
Ancestry has announced testing of a customized chip. Tim Janzen spoke with Ancestry about the new chip. Tim is a medical doctor and an expert in genetic genealogy. He says Ancestry has maintained 400,000 nucleotides for cousin matching and 300,000 for ethnicity estimates.
Ancestry says the changes are backwards compatible with the old test. Comparisons show customers get about the same match list as before. From these statements I’m guessing that the new and improved match algorithm recently released by Ancestry (see “AncestryDNA’s Cutting-Edge Science Gets Even Sharper” on the Ancestry blog) is designed to support both old and new chips.
Ancestry has added some nucleotides to help matching outside Europe. A few markers were added for health testing. Since Ancestry isn’t currently licensed to provide health test results, those results will remain unreported, at least for now. According to Ancestry, “We continue to explore the possibility of developing health products in the future, and may do so with proper regulatory and legal approval.” Ancestry states that “if you’ve already taken an AncestryDNA test, you don’t need to take a new test for the existing features of our service to continue to work.” (Emphasis added.)
I’m wondering if the new tested nucleotides are in addition to the ones previously tested or if they replace some. Illumina may have improved their chip technology, providing more nucleotide tests. Or Ancestry may have reallocated some. I’m guessing they have reallocated some for medical testing and improved ethnicity estimates outside Europe.
For more information, see “Customer Testing Begins on New AncestryDNA Chip” on the Ancestry Tech Blog and Tim Janzen’s 16 May 2016 email message, “Upcoming Changes to the AncestryDNA Test” on the RootsWeb AUTOSOMAL-DNA mailing list.
Image credit: “Infinium OmniExpress-24 v1.2 BeadChip,” PDF file, Illumina (http://www.illumina.com/content/dam/illumina-marketing/documents/products/datasheets/datasheet_human_omni_express.pdf : accessed 28 May 2016), 1.