The 6-Billion-Base Athlete

"We can rebuild him. We have the technology."

Remember that opening line from the Six Million Dollar Man? Soon we'll be able to genetically rebuild people. Or at least add some cool new features...

Let’s say we wanted to make an athlete stronger or able to run for a longer amount of time. One way we might do it is to add a certain version of the EPO receptor gene to build up his or her endurance. Or a certain version of the myostatin gene to make the athlete stronger.

How would we add these genes? Most likely with something called viral-mediated gene therapy. The first thing we'd need to do is find a virus that naturally inserts itself into DNA. There are lots of these around so that's pretty easy. Next we'd need to take out any viral genes that make the virus dangerous and replace them with the gene(s) we're interested in (EPO receptor and/or myostatin). Then we'd infect the athlete with the engineered virus and voila, a rebuilt athlete!

Sounds simple enough. But of course, reality is much more complicated. Just sticking a gene into a virus won't work. We'd need to put something called a promoter in front of the gene(s). A promoter is a DNA sequence that tells a cell that a gene is here so please make a copy of it into RNA. (The RNA is then translated into a protein that does something like make extra red blood cells or bigger muscles.)

We'd also want the gene read only in the right cells. We can accomplish this by either infecting only the cell type we want or by using a promoter that works only in a certain cell type. The best bet for the EPO receptor is to remove bone marrow cells, infect them with the virus and put them back. Viruses with the myostatin gene would probably need to be injected directly into the muscle.

We'd also need a lot of the right kind of cells to get the gene. One way to do this is to add a lot of virus. But this can be dangerous and has even killed people. Another way is to put some sort of selectable marker on the virus. This would work best for the EPO receptor. The idea would be to include something that would just be on the cells that got infected. Then we would put only the selected cells back into the athlete. Now we have bone marrow all making the right EPO receptor.

A big danger with viral mediated gene therapy is we can't control where the virus lands. Sometimes when a virus lands near a gene, it'll turn that gene on. And if that gene shouldn’t be on, bad things can happen. Like cancer.

This exact thing happened in gene therapy's best “success” story. Ten kids in France were cured of a "bubble boy"-like disease using gene therapy. Unfortunately, two of the children developed leukemia. Both responded well to treatment and are doing fine but leukemia is pretty scary. Especially when we just want to hit a ball farther!

Scientists have sometimes made gene therapy work but I don't yet know of an unqualified success story. But athletes are willing to risk the side effects of steroid use, so I suppose they'll risk this as well. Next blog I'll talk about whether or not we could catch them. Or at least whether it'll be harder or easier to spot than designer steroids.

More about gene therapy.