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Citing Throughput Advantages, FTDNA Joins 23andMe in Moving to New 24-Sample Illumina Chip Format


This story has been updated to include comments from

Family Tree DNA will next month begin using a new, higher-throughput microarray format to process samples for its genetic genealogy service.

David Mittelman, chief scientific officer for Gene by Gene, of which Family Tree DNA is a subdivision, told BioArray News this week that the Houston, Texas-based company will run samples on new, 24-sample Infinium BeadChips manufactured by Illumina. Family Tree DNA had previously used the San Diego vendor's 12-sample OmniExpress BeadChips in its service.

"The biggest value of a 24-sample chip instead of the older 12-sample chip is that you can run twice as many samples," said Mittelman. "Running double the samples means we can process more samples at a time and then people can get their data faster," he said.

Mittelman noted that it will still take the same amount of time to process samples submitted to the company's autosomal DNA testing Family Finder service, currently about three weeks, but the company will be able to analyze more samples at a time, so it won't "run into backlogs as often." He added that, independent of adopting the new chip format, the company has refined its sample analysis process to decrease turnaround time where possible.

Family Tree DNA is the second big consumer genomics player to move to Illumina's newer, 24-sample arrays since the firm announced the launch of the new chips in October. Last month, 23andMe said that it would move its services to a custom array manufactured in the new format. Like Family Tree DNA, 23andMe had previously used Illumina's OmniExpress.

An company spokesperson told BioArray News this week that will also be moving to the new 24-sample array format, but said that the company would not change content of the arrays used in its service.

National Geographic's Genographic Project has used a custom, 130,000-marker Illumina HD iSelect BeadChip since it rolled out the second, array-powered phase of the project, called Geno 2.0, last year. Genographic Project Director Spencer Wells told BioArray News in August that the organization is currently at work on a new array that will succeed its current chip.

Unlike 23andMe, Family Tree DNA is using Illumina's catalog HTS-24 arrays to process its samples. Each array on the chip contains 750,000 SNPs, a slight decrease in coverage from Family Tree DNA's previous generation array. However, Mittelman said that the change in content will not impact Family Tree DNA's service.

"The new format has less probes — so you get less SNPs, but this does not automatically mean you get less information," Mittelman said. "We currently use our chips only for genealogy, so we sample more positions on the genome than we need," he said. "The reduction in chip size doesn't really impact us and we expect the user experience to be unchanged."

According to Mittelman, Family Tree DNA has already upgraded its hardware to process the new chips, which are being validated ahead of a January roll out. He added that it will be a "seamless transition" for Family Tree DNA customers.