Monday, 3 October 2011

A side order of exomes?

If you're a current 23andMe.com customer you can now apply to be included in a pilot project, Exome 80x, which will provide a complete sequence of the 50 million DNA bases in your exome, the part of your genome containing the information necessary to encode all your proteins.

The cost, if selected, will be $999, which if memory serves is the price the company put on its original service.

For that you get a data set from an analysis, repeated 80 times to ensure accuracy, of those 50 million DNA base pairs.

I've been asked if this will be useful for ancestry investigations.

The company web page is managing down expectation for genealogical significance:

"Exome data are less suitable for ancestry or genealogical research, since they will not provide mitochrondrial sequence or much information on the Y chromosome."
Blaine T. Bettinger posts on his Genetic Genealogist blog
",,, 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."
Behind his thoughts is the idea of investigating "rare variants in genetic disorders" and "disease-causing mutations."

However, the exome accounts for only about 1.5% of the total genome, and although it codes for proteins I know of no finding indicating the 1.5% in the exome is any more important for ancestry analysis than the other 98.8%.  In fact the STRs widely used for genealogy, and as the CODIS markers for criminal and traditional paternity investigations, are outside the exome.

In addition for the average genealogists, even one with $999 to spare, they are still in for a hard slog to get anything useful out of that 50 million base pair data that will be available as raw data without interpretative tools, although 23andMe indicates they may come later.

This is one I'd advise all but the most leading edge genetic genealogist to let pass for the time being. I'd rather use those funds on airfare to the UK for some hands on documentary research.

1 comment:

Anonymous said...

In the following quote from this post 1.5% plus "the other 98.8%" makes 100.3%. If the 1.5% is correct should not the other be 98.5%?

"However, the exome accounts for only about 1.5% of the total genome, and although it codes for proteins I know of no finding indicating the 1.5% in the exome is any more important for ancestry analysis than the other 98.8%."