THE BLOG

23andMe and Me: Personal Genomics Coming of Age, Part 2

10/17/2012 12:04 pm ET | Updated Dec 17, 2012

In my first piece on personal genomics, I wrote about how data on one's genome delivered by companies such as 23andMe can provide information on one's disease risk. Such personal genomics studies estimate the probability of someone getting a disease.

The exception to this rule of genomics probability as opposed to certainty with genomics is the case of specific so-called "disease alleles" that are known to definitely cause diseases such as Tay-Sachs Disease. A second 23andMe tool, called "Carrier Status," specifically tells you about these disease-causing alleles. What this means is that if you are a carrier of a so-called "disease variant," your DNA has within in it a certain element that causes specific diseases almost without exception. Therefore, unlike the probabilistic nature of most genomics, carrier status is all about certainty. If you are the carrier of a snippet of DNA that is recessive for a disease, if you have two copies of the element, with only rare exceptions you will definitely get the disease yourself; but if you have one copy, you will not get it. However, if you and your reproductive partner both have one copy, then your children have about a 25 percent chance of having two copies and getting the disease in question. Of all the variants listed, I had none, so that was good news. Some people who have found out they are carrying one disease allele through the service of 23andMe now have a very valuable piece of information with which to make reproductive choices, and might want their prospective partners to be tested for that allele.

23andMe also has a "Trait" tool that predicts what your traits such as height, hair color and so forth are likely to be, based on your DNA sequence. The Trait tool got just about everything right about me. In other words, the language of my DNA, my genome, as translated by 23andMe had me pretty well pegged: freckles, slightly curly hair, correct blood type, average height, and so forth. According to two 23andMe team members mentioned in part one of this personal genomics series, Catherine Afarian and Joanna Mountain, one way in which 23andMe makes predictions about how certain segments of DNA predispose people to specific traits and diseases is through mining the scientific literature for genetics and genomics studies. In fact, 23andMe has what is called a "curation team" of five Ph.D. scientists who troll the literature for new genetics and genomics studies that link up specific DNA sequences with certain traits and diseases, which are collectively known as "phenotypes." The team then incorporates that data into the ever-growing library of information that 23andMe uses for their analyses. Interestingly, in addition, 23andMe also gains knowledge by conducting surveys of the more than 100,000 people within its community who have had their DNA analyzed. "At first we weren't sure how open people would be open to answering the questions in the surveys," said Afarian, "but it turns out that they are very open." Mountain added that so far members of the 23andMe community have enthusiastically responded to the surveys, together "answering around 48 million questions."

Based on the answers about disease traits cross-referenced with the answerers' specific DNA, 23andMe is able to conduct cutting-edge research on how certain genomic elements are related to traits and diseases. In that way, 23andMe publishes on average a few papers a year. For example, they recently published a study on genetics and Parkinson's disease. Such efforts have been termed "crowd science," where groups of people working together can advance knowledge. When it comes to 23andMe members, there is a great deal of interest in actively participating in personal genomics. Afarian noted that members are engaging in an ongoing dialogue with 23andMe, which is very responsive to not only questions, but also ideas from customers. For example, 23andMe customers have shown a great deal of interest in the potential role of genetics in influencing sexual orientation, although that is not currently a trait listed in 23andMe results.

One of the most popular tools on 23andMe is called "Relative Finder," which quite literally means what its name implies. Using this tool, based on one's DNA sequence, a 23andMe customer can see who amongst the 23andMe community of more than 150,000 people are your relatives. For some folks, this has led to the discovery of previously unknown very close relatives such as siblings. In my case, as the first person in my apparently fairly reproductively boring, immediate family to do 23andMe, I found no shocks of new siblings or anything like that, but there were a very large number -- more than a hundred, in fact -- of new cousins out there. According to Afarian, given the number of genomic segments that I share with these relatives, some of them almost certainly share great- or great-great- grandparents with me, which I found very intriguing. Unlike Ancestry.com, which is one of the few even remotely similar competitors of 23andMe out there, 23andMe finds real, living, breathing people. Ancestry.com predominantly identifies dead relatives, which is still quite interesting to me, but not quite the same.

Now that my mom and my two brothers have also done 23andMe, I can subsequently see them listed as my relatives on my 23andMe webpage. 23andMe also allows family members, if so inclined, to share their genomic information. My mom, my two brothers and I have shared our genomic information, leading to some interesting discoveries via 23andMe. For example, I am more similar to my brothers than to my mom. I asked Mountain about this and she said that while children's genomic similarity to their parents is largely fixed, just how related you are to your siblings can interestingly vary a bit. I can also see when comparing our family's DNA that my brothers and I are not only the same blood type, but share every minor component of blood type but one. Fortunately for my two brothers, according to 23andMe they share 100 percent immune compatibility, indicating they could likely give each other organs or bone marrow if needed. No such luck for me, as I'm not much more similar to them on the immunological front than to strangers.

It is important to note the competitors of 23andMe out there that do genomics and genetics analyses. One of them could potentially wrestle the leading spot from 23andMe in the future. Who are these competitors? deCodeme is a competitor that does DNA analysis, but charges $1,100. It also is not clear that deCodeme has any way to find relatives. Another player in the arena is Pathway Genomics, but a disadvantage there is that they do not sell a direct-to-consumer product, meaning you have to do everything via your physician. I had trouble finding out the cost. Competitor Navigenics has been purchased by Life Technologies, and as of August of this year no longer is taking new customers. Since I've not used these other services, it is impossible for me to compare them with each other or with 23andMe. I suspect as personal genomics continues to enter the public consciousness, there will be even more companies out there, each working to find a sustainable business model.

Stay tuned for part three of these series, where I will focus on the potential serious downsides to personal genomics, how personal genomics may provide different experiences for those with various ethnic backgrounds, and what the future holds for personal genomics as well as its impact on society.

Disclosure: 23andMe gave me a free analysis of my genome at my request as I was researching this article on personal genomics. I have no financial interest in the company.

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