Should their ACTN3 gene version exclude some of these folks
from marathons? Photo by Monica Darby.

This scenario is not as far fetched as it sounds. A genetic test is available that claims to be able to help parents predict what sports their kids will be good at. The idea is that the parents can then funnel their kids into the sports at which they are most likely to succeed. How scary is that!

As I said, the test looks at the ACTN3 gene. Some work has been done that shows that elite athletes with one version are good at sports like football or sprinting. And that elite athletes with another version are good at sports like marathons.

But this gene is just one of many involved in determining how good someone will be at a certain sport. One of the key researchers who identified this gene has written that it can only really account for 2-3% of muscle variation in the general population. In other words, it is just one of many factors involved in making a star athlete.

So this genetic test might be able to distinguish an Olympic athlete from one who doesn't quite make the team. But how many kids does this really apply to?

Even if a genetic test could tell everything about a person's muscles, I would still think it is awful to restrict a child's choices of sports based on that sort of genetic test. Let me give you a hypothetical for why I find this sort of testing so troubling.

Imagine that instead of this test, there is a reliable one that will accurately predict someone's height*. Let's say a family has the test done on their son and they find that he will grow to be 5′3″.

The family steers the boy away from basketball because height is so important in that game. If this actually happened, then the NBA may never have had former pro Mugsy Bogues.

A genetic test that looks at a single trait to determine a person's future is dangerous. Should someone not be introduced into a sport because of their genes? Really?

A genetic test for height won't look at determination. Or speed or ball handling or all of the other traits that made Mugsy such a great player for 16 years.

And the ACTN3 gene test doesn't look at lots of other important traits too. In fact, it won't predict whether your child will be a super athlete or necessarily even good at football vs. a marathon.

Even if a test were developed that looked at all of these traits, should parents use it to control the sports their kids can play? What about their child's interests? Should Mugsy's parents have taken the basketball away from him even though he obviously loved the game?

Just let the kids play! Genes are not destiny.

*This sort of test is a long way off. Scientists only recently found the first "height" gene.

Did John's genes make him cheat on Elizabeth?
Photo by Mike Murphy

The gene commonly comes in three different versions — RS1, RS3, and GT25. Men with GT25 and RS1 reported more infidelity and had unhappier marriages on average than men with RS3. Which version a woman had didn't seem to matter.

Scientists don't know why men with the RS3 version are more faithful but it makes sense that this gene would be involved. It has been implicated in pair bonding in other animals with the best and most comprehensive work having been done on little rodents called voles.

There are many different kinds of voles but we’ll focus on prairie and meadow voles. Prairie voles stick with one female. Meadow voles are a bit more like men in country music songs — they tend to love them and leave them.

A bunch of wonderful experiments showed that the voles' different behaviors were because they had different versions of a certain vasopressin receptor gene. People don’t have the exact genetic difference that meadow and prairie voles have. But the exact same gene is involved in this new study.

The vole experiments showed that if the vasopressin receptor works less well in prairie voles, the boy voles develop a wandering eye. And male meadow voles with extra potent vasopressin receptors settle down.

So at least in voles this vasopressin receptor gene is important for pair bonding. We'll need more studies in humans to nail down whether it plays as big a role in human male monogamy. But this study does bring up some interesting ideas.

First off, we aren't voles so having this gene is no excuse for cheating on a partner. It just means that it is harder for these men to remain faithful. Sorry John but even if you have this gene version it doesn’t let you off the hook for cheating on Elizabeth.

Second, if the study proves to be correct, then it suggests that there may be a pharmaceutical way to modify men's behavior. A pharmaceutical company would need to come up with a drug that targets this receptor. Now men who take this drug would be more likely to be faithful. I don’t know about you, but this form of pharmaceutical behavioral modification seems a little scary to me.

Transcaucasian mole vole. Image Courtesy of Heike HimmelreichOne of my favorites is a little burrowing mammal called a Transcaucasian mole vole. These guys live in the Caucasus Mountains of Armenia, Iran, Turkey, and Azerbaijan. There they are born, live, have babies and die. All without a Y chromosome.

This is really bizarre. In most mammals, two X chromosomes usually means that the animal is female and an X and a Y means the animal is male. All mole voles have a single X chromosome. So technically, there shouldn’t be any males running around. And yet, clearly, there are.

So what distinguishes a boy mole vole from a girl mole vole genetically? No one really knows.

In most mammals, the Y chromosome causes a fertilized egg to turn into a male because of the SRY gene. This gene starts a cascade of events that eventually results in a male.

One possibility would be if the SRY gene happened to move to another chromosome. There are certainly cases of this happening even in humans.

If this were the case, then maybe a different chromosome has the SRY gene in mole voles. Maybe there are versions of the gene that work and versions that don't. Now we have a gene no different than an eye or hair color gene.

Good model but it isn't true. Scientists have looked but it appears that these little guys don't have an SRY gene. They make the male/female decision in a completely different way.

Most likely somewhere along the way a gene mutated so that it could now determine the sex of these mammals. When this happened, the loss of the Y didn't matter much and so it was lost. The mole vole evolved into a Y-less mammal.

Of course, if any chromosome had to go it would be the Y. It has been under constant attack ever since it distinguished itself from the X chromosome 200 or 300 million years ago. It has gone from being one of the biggest chromosomes with 900-1400 genes to a bit of DNA with around 80 genes.

There are even active discussions about whether the Y is on a death spiral in all mammals. Soon we may all be mole voles. Or be gone. Some of my recent posts elsewhere on this topic:

Males going extinct?
Fish that change gender

So much information, so little understandingOn June 9, the California Department of Public Health (CDPH) sent letters to 13 different direct-to-consumer genetic testing companies telling them that they were not in compliance with California laws and needed to stop providing testing. The two main issues appear to be:

1. The testing facilities were not licensed correctly.
2. The tests were ordered without the request or counsel of a doctor.

This seems to me to be the opening salvo in an upcoming war between the government and these companies about DNA testing. The government wants to protect the consumer from getting incorrect results and/or misinterpreting the results they get. The companies want to provide people with information about their own DNA. I have to say I am unsure where I stand on this one.

On the one hand, there are some companies out there selling snake oil. For example, anyone claiming that they can provide a set of nutritional products based on your genetic test results almost certainly should be shut down.

And I would guess that the CDPH is not going after purely recreational companies like those involved in ancestry. I can't imagine why a doctor would order that kind of test. If these letters target ancestry companies, then whatever laws are involved should be changed.

There are also companies that comply with the current California laws. One of the most prominent is DNA Direct. This company follows all of the rules of the state, only offers well validated tests that are performed in a CLIA lab, and provides genetic counseling so people can understand the results they get.

But what about the companies between DNA Direct and ancestry testing services? Although we don't know for sure, the CDPH seems to have targeted many newer companies that look at hundreds of thousands or even millions of DNA differences at once throughout a person's DNA.

The three main companies that I know about that are in this gray region are Navigenics, 23andMe, and deCODEme. Navigenics is a different sort of beast from the other two in that it only provides information on DNA differences that have a well established link to a disease and they also provide genetic counseling. The other two can really be thought more of as recreational genomics at this point.

23andMe and deCODEme give a client all of their information and then tell the client what is known about each DNA difference. They offer ancestry, trait, and disease information bundled up in a single 1000 dollar test.

These companies count on the consumer being able to digest all of that data and recognize what is a strong and/or important correlation and what is not. This is the point where a group that includes the government, doctors, and many academics differ with these companies.

Once we make sure that the testing is done well, the question really boils down to whether or not the consumer can handle all of the information*. Can consumers interpret these kinds of results and know when to seek help and when not to?

The answer is that some can and some can't. So how do we protect those who can't but still allow people access to their own DNA? Or should we protect consumers at all from their own DNA information?

*There is also the stipulation about a doctor ordering the test but frankly I don't get that one and am not sure it should be part of any consumer protection.

Copy of the letter from Wired Science

There are many others also working in the field. The Alzheimer's Association has information about current treatments available. The National Institute on Aging gives a good overview of what avenues of research are being pursued to better diagnose the disease and find a cure. A team of health professionals at the UC Davis Alzheimer's Disease Center can provide a diagnostic work-up, as well as enroll patients in several ongoing clinical trials.

Watch the "Alzheimer's: Is the Cure in the Genes?" TV Story online, as well as find additional links and resources.

Gabriela Quirós is a Segment Producer for KQED-TV, and is the producer for this story.

Red hair genes will be diluted but will not go away.

The guy from the bookstore must have read one of the stories about the imminent demise of redheads that flashes across the media landscape every few months. People with red hair have to deal with headlines like:

"Redheads Set for Extinction."
'Will rare redheads be extinct by 2100?'
"Gingers Extinct in 100 Years."

The reporter suspected these stories weren't right and wanted to write a story about it. She called me to get some science to back her up. I was able to reassure her that redheads weren't going the way of the dodo. They'll become much less common, but there will probably always be red haired people around.

To understand why redheads will fade but not disappear, we need to dig a bit deeper into how red hair works. Red hair happens when both copies of the MC1R gene do not work properly. (Remember we have two copies of almost all of our genes–one from mom and one from dad.)

So if you're a redhead, you inherited a nonworking copy of MC1R from both your mom and your dad. If you get a non-working copy from only one of them, then you won't have red hair. You'll be a carrier.

Right now redheads are at an artificially high level in the human population because their recessive red hair genes are concentrated in North America, Europe, and Australia. For example, 10% of Ireland and 2-6% of the U.S. has red hair.

These numbers are maintained because carriers and redheads keep making new redheads with each other. But as barriers go down, their red hair genes will flow out of these populations and into the human gene pool.

Red hair genes will become diluted in this pool but they won't be completely swamped out. Even as redheads decline in numbers, their genes will remain constant. It will just be less likely that two carriers and/or redheads will meet and have babies with red hair.

This is all interesting but it got me to wondering about how many redheads there will be in the distant future when all the mixing is said and done. We can use something called the Hardy Weinberg equation to figure this out.

This equation works great for simple dominant/recessive traits like red hair if we know how many of each gene version there is. To do this, we need to figure out how many redheads and how many carriers there are in the world.

It is easy to figure out how many redheads there are–you can tell who they are just by looking at them. But figuring out carriers is a lot harder. We can make guesses based on the number of redheads (again using Hardy Weinberg) but until we sequence a lot more MC1R genes, they'll only be guesses.

The numbers I have seen floating around are that around 1% of the world's population has red hair and that around 4% carry the red hair version of MC1R. This means that there are around 65 million or so redheads in the world and 260 million carriers. (This sounds high to me but these are the numbers out there.)

When we use these numbers and apply the Hardy Weinberg equation, we end up with a final percentage of redheads of 0.1% or 6.5 million. This is quite a fall from current levels but they are hardly wiped out!

There are lots of assumptions* in these calculations that might cause the number of redheads to actually be more or less than 0.1%. But unless there is some red hair specific catastrophe or people start burning them as witches again, redheads are here to stay.

Dr. Barry Starr is a Geneticist-in-Residence at The Tech Museum of Innovation in San Jose, CA.

*Some assumptions used:

1) There are no barriers to finding partners
2) The 4% carrier number is an accurate one
3) Two non-workingMC1R genes produce red hair in all genetic backgrounds
4) Other assumptions described here

Let me explain. On New Year's Eve I brought my phone with me to San Francisco's Ocean Beach, where I traditionally go, rain or shine, to watch the year's last sunset. I was by myself, but I wasn't alone.

Oh no. I took snapshots of shimmering colors on the waves and sent them to faraway, landlocked friends who miss the sea. Another friend called to say she was also watching the sunset from her rooftop. Text messages flowed in.

I was connected.

Well, duh," you could say.

And this "duh" is exactly what seemed kind of profound: we take communication for granted. Of course we can talk to each other and share things with each other. And of course we create new devices to make talking and sharing easier. Of course.

But why do we do this, seemingly to no end? And why is it that communication is such a vital and defining aspect of our experience as humans? Why, really, do I love my cell phone so much?

I think it's genetic.

It's probably not news to most of you that we humans appear to be wired to talk to each other. We've got that FOXP2 gene that keeps making the news, contributing to our linguistic capacity. In fact, many researchers believe that language was central to our success as a species and allowed a small group of humans to expand across the globe about 50,000 years ago.

Our genetic design for interaction seems to go beyond talking amongst ourselves. A University of Michigan study slated to be published next month found that social interaction has a positive affect on memory and on cognitive functioning. The people who had the most conversations with others seemed to be the sharpest, and this was particularly true among young people. This may mean that more socially-oriented humans had a bit of an advantage over those who tended to keep more to themselves.

We may be such social animals that we're even hard-wired to simply need company. After all, isolation is one of the most universal methods of punishment. Another set of researchers at the University of Illinois at Chicago found that mice isolated from their comrades have lower levels of hormones that control anxiety, depression, and aggression. They believe that these responses are similar in humans. In other words, it's possible that our brains keep us happier and functioning better when they're interacting with other brains.

It makes sense that our predecessors who figured out how to play well with others and share their thoughts were the ones who got the best shot at passing on their genes. And it's no wonder our species devotes such enormous reserves to inventions that make communication easier. The most basic systems of rock painting and alphabets have allowed groups to share stories or warn others of impending trouble. And creations that help disseminate these symbols–papyrus, the printing press, even the simple pen and paper–have had a major impact on how we exist with one another, as individuals and as societies.

These days, many of our communication technologies have gone beyond "watch for hungry bear" or "here's my idea" into doing a kind of doubly-human duty. We not only use technology to convey thoughts, but also to extend our opportunities to create bonds with other people and to form social groups. Thus the popularity of the likes of Facebook, personals ads, and Flickr. In fact, if you leave a comment about this little ditty I've written, you've hopped on this double-duty train by becoming a part of Quest's blogging community.

And so now, as my thumbs feverishly tap out text messages, I see my cell phone as more than a gadget. It's the latest cousin of cave drawings and hieroglyphics. What it says about my own evolution I'm not quite certain. But no doubt my wireless admiration results from something buried in my chromosomes.

Robin Marks is a journalist and science writer who current serves as a Multimedia Projects Developer for the Exploratorium in San Francisco, CA.

latitude: 37.7595, longitude: -122.51