It’s been an exciting seven months since we launched 23andWe, the arm of 23andMe that gives people an unprecedented opportunity to collaborate with us on cutting-edge genetic research. Since May, the amount of data we’ve collected has grown at a fast and furious pace. For those of us who are used to the difficult and painfully slow accumulation of data in academic research projects, this information explosion has been nothing short of amazing.

From our first baby steps with “Ten Things About You” in May, to our three latest surveys — “Health Habits,” “Where Are You From?” and “What Do You Do?” — 23andWe has undergone some serious evolution. Almost every month, we have published more surveys and developed more features to help make the survey-taking experience simpler, more interesting, and more rewarding. We want to make it easy for our customers to provide truthful, good quality data, as that is the first and most important step towards doing high quality research. A big thank you to all our survey takers—we pledge to constantly work on improving this feature so we can keep you coming back for more.

We’re starting to look at genetic associations with the traits we ask about in our surveys, and we expect to have some exciting ones to report soon. But we’ve already learned some interesting things just by looking at the survey responses themselves. For example, while a few sources suggest that a higher percentage of men are left-handed than women, our data so far suggest that once you control for age this is not the case. It seems like our society is becoming more accepting of us female lefties! We’ve also seen that handedness does indeed significantly correlate with footedness. That is, left-handers are more likely to be left-footed, and right-handers are more likely to be right-footed. Similarly, handedness significantly correlates with ocular dominance, as left-handers are more likely to be left-eye dominant, and right-handers are more likely to be right-eye dominant.

And proving mom right once and for all, we’ve found that a sweet tooth does lead to more cavities. After controlling for sex and age, you’re more likely to report having many cavities (as opposed to few or none) if you reach for either something sweet or something sweet and salty when it’s time for a snack.

How is this kind of information going to usher in the era of personalized medicine? Handedness may seem like a relatively trivial trait, but it is correlated with risk for learning disability, schizophrenia, exceptional mathematical talent and other relevant traits. Understanding the biological underpinnings of what makes us choose one hand over the other for all our most delicate tasks may help us better understand the basis for these other complex traits.

As 23andWe matures we plan to start focusing more directly on health-related traits. Look for surveys in the very near future that ask about various medical conditions whose genetics is not yet understood. By combining the information customers provide in their survey responses with data from our custom chip, we can look throughout the genome for DNA variations linked to many different traits. This method can help us find genes that no one thought would be involved with a particular condition. For example, genome-wide studies on age-related macular degeneration (a leading cause of blindness) recently surprised researchers by identifying associations with genes that make components of the innate immune system. This gave scientists a whole new pathway in which to search for treatments.

We can’t guarantee that we’ll find something useful or interesting with every analysis that we do; science is a game you have to play a lot of times in order to win. But we can guarantee that we will strive to do the best research and that we will share our findings with the scientific community. By contributing to the body of knowledge on human genetics, we believe we can help bring the dream of personalized medicine a few steps closer to reality.

And all we need you to do is take some surveys.

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You may have already read about 23andWe and the ”Power of We” in earlier blog posts. As the research arm of 23andMe, we’re hoping 23andWe can produce valuable discoveries about the genetic roots of diseases, conditions and traits that are little-studied due to funding limitations, logistical obstacles or simple lack of interest among scientists. 23andMe’s payoff could prove enormous by offering insights that may eventually lead to risk predictions, diagnostics, treatments or even cures for diseases.

At 23andMe, we are all about grand ideas with big potential, and we are committed to realizing our vision, but how do you even start such a big project? You begin at the beginning, of course.

When we first started thinking about the traits we wanted to study in 23andWe, we faced a big problem. Out of all the possible traits out there, which ones should we study first? It’s both an overwhelming and wonderful problem to have, and one, I think, that is pretty unique in the scientific community.

Most academic human genetics labs don’t have the luxury of splitting their research resources amongst many different problems. Subject recruitment, genotyping, and analysis are so difficult and expensive for even one trait that it’s usually feasible for only the largest and most well-funded centers to do this type of work. Limited funding usually also means that only the traits and diseases that are considered really serious get studied.

In 23andWe, we saw a unique opportunity to tackle interesting and important questions about biology and disease that have so far been largely left unanswered.

Focusing on what has traditionally been understudied helped narrow down our field of research questions a little bit, but not that much. Frankly, not that many traits and diseases have been studied very well. So we had to apply a few more filters.

We wanted to pick topics that
• Are relatively simple, because we have to walk before we can run.
• Are easy to capture accurately over the Internet (which for now will involve online surveys).
• Will apply to a wide swath of the population.
• Already have some evidence in the literature for having a genetic basis

I can’t tell you how many PubMed (a biomedical literature search engine sponsored by the National Institutes of Health) searches we’ve done, nor how many 40-, 60-, and 80-year old papers we had to dig up to find some of the information we needed.

It’s been a fascinating project to work on. Did you know that people have been studying the inheritance of tongue curling for close to 70 years ? Turns out it’s not the simple Mendelian trait your high school biology teacher told you it was. Instead, tongue curling ability is probably determined by a mix of genetic and environmental factors.

It’s not all about tongue curling though. We’ve also been delving into the literature on many more serious health issues that affect large segments of the population but have not yet received as much attention as they deserve. These topics range from dyslexia, to endometriosis, to migraine. We plan to collaborate with experts in the scientific and medical communities to push forward the limits of our knowledge on these important topics, with the long-term goal of helping to improve the quality of people’s lives.

In the coming months you’ll start seeing the fruits of our labor as we roll out our first 23andWe projects. Of course, this is just the beginning. We’re going to spend countless more hours scanning our PubMed search results and fighting with the scientific journals’ user-unfriendly websites. And our thought processes, methods, and goals will continue to evolve as we gain experience and accumulate data. But it’s all worth it, because the rewards are potentially great.

Stay posted…

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But have you ever thought about what controls your appetite? What if your body didn’t tell you to stop eating when you’d consumed enough calories?

You’d gain weight, that’s what. It’s long been known that mutations in a gene called MC4R cause mice to become bigger and fatter than their regular counterparts. It’s thought that eating a lot causes the body to turn on MC4R, which in turn tells the mice to stop eating by making them feel full. There are also rare variations that disrupt the human MC4R protein and cause children to eat too much, leading to severe childhood obesity.

Interesting, you say, but does this apply to the general population too? Research published online Sunday in the journal Nature Genetics suggests that the answer is yes.

A large study of over 77,000 Europeans by Loos et al. found a SNP near the MC4R gene, rs17782313, that was strongly associated with body mass index (BMI), a measure of obesity. (To calculate your own BMI, go to: http://www.nhlbisupport.com/bmi/bmicalc.htm) They found that each copy of the C version of rs17782313 was associated with an increase of 0.22 BMI units in adults (for a person of my height, 5 ft 3 in, that’s a little over a pound). In children, they found that this SNP had an even larger effect. Unlike the rare changes in MC4R that cause severe childhood obesity, 30 to 50% of the population has at least one copy of the C allele of rs17782313.

A second paper by Chambers et al., also published online Sunday in Nature Genetics, studied more than 14,000 Indian Asians and Europeans and found that a different SNP near MC4R, rs12970134, is associated with waist circumference. Each copy of the A version is associated with a 0.88 cm (0.3 in) increase in waist circumference. That means that on average, the waists of people with two copies of the A version of rs12970134 are 0.6 inches larger than the waists of people with two copies of the other version of the SNP. Talk about pinching an inch!

23andMe customers can use the table below to figure out what these SNPs mean for them. While we do not genotype rs17782313, we do genotype rs10871777, which is considered equivalent to rs17782313 in Europeans and Asians. The C version of rs17782313 is equivalent to the G allele of rs10871777.

Fortunately for most of us, genes are only one player in our risk for obesity, as our behavior and environment can still play a large role in maintaining a healthy weight.

Calculating your BMI: You can calculate your own BMI using the following formula: multiply your weight in pounds by 0.454 to get your weight in kilograms. Then multiply your height in inches by .0254 to get your height in meters and square the result. Divide your weight in kilograms by your height in meters squared to get your BMI. A BMI less than 18.5 is considered underweight, between 18.5 and 24.9 normal, between 25 and 29.9 overweight, and above 30, obese.

Photo by Julie de Leseleuc/istockphoto

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The fact of the matter is that much of the research on the genetic factors that influence diseases is done in countries where people with European ancestry make up a majority of the population. As a result, the studies are done in groups that are mostly or completely Caucasian, and we can really only be sure the study results are only known to be valid in people with the same ancestry (actually the results might not even be valid in all people with European ancestry, but it’s the best we can do with the available science).

Yet, you may still wonder, isn’t DNA universal? Why wouldn’t a SNP that makes a Swedish person a good sprinter also make a Korean person a good sprinter?

In cases where a SNP directly affects the trait in question, it is very likely to be true that the different versions of the SNP do work the same way in everyone. But in many cases, the SNPs that researchers find in their studies are just stands-ins for DNA changes that actually affect the traits they’re investigating. We say that these stand-ins are “markers”. In the same way a sign on the highway might tell you that there are restrooms and gas stations at the next exit, a marker SNP tells you that a functional DNA change is nearby.

(Read on to learn about marker SNPs and ancestry)

Now let’s imagine that some prankster steals the highway sign and puts it next to some other exit that has no restrooms or gas stations. Because the sign has been separated from the exit it was originally next to, it is no longer informative. Similarly, if a marker SNP is separated from the functional DNA change it was originally next to, the marker is now uninformative.

How could a marker SNP become separated from the functional DNA change it was pointing to? The answer is recombination—the shuffling of DNA that takes place when sperm and eggs are made. (Click here to learn more about recombination)

Historically, major populations were reproductively separated from each other. That is, people from one group tended to have children with people from the same group. Since DNA shuffling during recombination occurs pretty randomly, each population developed its own unique shuffling pattern.

So it’s possible that a marker SNP and a functional DNA change that are linked together in one population got shuffled away from each other in a different population. This means, for example, that if a version of a SNP is associated with disease susceptibility in people with European ancestry and it turns out to just be a marker SNP, it might be uninformative in people with Asian or African ancestry (if it got shuffled away from the functional change in those populations). The same goes for people with mixed ancestry. A marker SNP may or may not turn out to be informative for them.

The difficulty is that scientists usually don’t know if the SNPs they find in their studies are marker SNPs or functional DNA changes. That’s why it’s important to repeat genetic studies in different ethnic groups to see if the SNP associations with certain traits are true for people of different backgrounds. We at 23andMe hope to perform our own research in a diverse set of peoples to help customers the world over understand more about their genetics.

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