Yesterday, at Health 2.0 in San Francisco, 23andMe announced that it will be offering sequencing of exomes with 80x coverage for $999. At Exome 80x, 23andMe discusses their test:
Your exome is the 50 million DNA bases of your genome containing the information necessary to encode all your proteins. Informally, you can think of the exome as the DNA sequence of your genes.
Your entire genome is made up of your exome plus other DNA, consisting of three billion bases with repetitive sequences, sequences of unknown function, and DNA that does not code for proteins.
Note that the Exome 80x test is only available to current customers, and is determined on a “first come, first served” basis. Further, test-takers will initially only receive their raw data of 50 million DNA bases at 80x coverage, but 23andMe plans to develop new tools to take advantage of exome sequencing.
Many non-geneticists will no doubt be wondering what the “exome” really is. The exome is the protein-coding portion of your genome, and comprises roughly 1.5% of the total genome.
For insight into what type of information might be gleaned from exome data, Daniel MacArthur has an article entitled “Venter’s exome, and the challenge of rare variants for personal genomics” from August, 2008. In the article, he discusses some of the findings from the analysis of J. Craig Venter’s exome.
The Genealogist’s Exome
As a genetic genealogist, I was of course interested in the ramifications of exome testing on testing for genetic ancestry purposes. 23andMe states the following on their Exome 80x page:
Exome data are less suitable for ancestry or genealogical research, since they will not provide mitochrondrial sequence or much information on the Y chromosome.
This is a strange sentence, and one I believe wasn’t properly screened. In my experience few genealogists decide to pursue 23andMe testing for the mtDNA or Y-DNA results. It’s autosomal DNA testing and tools like Ancestry Painting and Relative Finder for which most genealogists use 23andme testing, and it’s far too early to tell whether genealogists will be able to make use of exome sequencing (of course we will!).
I hope this sentiment does not discourage genetic genealogists from pursuing the Exome 80x product. Genealogists have been – and continue to be – among the very first adopters of new DTC DNA testing (including 23andMe’s very first product back in the 2007 to 2009 time frame). Indeed, genealogists having been driving the DTC genetic testing market since 2000 with the launch of Family Tree DNA!
One of most exciting uses of the Exome 80x product might be in self-directed discovery of rare variants in genetic disorders. Numerous rare genetic diseases, many of which likely result from unidentified rare variants, have not been exhaustively studied. At least one group has estimated that 85% of disease-causing mutations are found in the exome.
I can envision 23andMe Community Projects for rare genetic disorders, similar to its Parkinson’s Community but much smaller in size, where several members of a family purchase the Exome 80x sequencing in an attempt to identify variants that might be involved in the disease. These projects may be sponsored and supported by 23andme, or might simply be a family attempting to analyze their genomes themselves.
- Daniel MacArthur points out over at Google+ (“A few initial thoughts on 23andMe’s new $999 exome product“), 23andMe is not the first company to offer DTC exome sequencing, as Knome has been offering their services for some time. 23andMe is, however, the first to offer such a product under the $1,000 price point.
- Matthew Herper has an article at Forbes.com discussing 23andMe’s launch (“The Future Is Now: 23andMe Now Offers All Your Genes For $999”).
Will you be signing up for 23andMe’s Exome 80x product?