Genes For…

A village in Ecuador has caught the attention of scientists interested in increasing how long we live. Some people in the village are immune to cancer and diabetes, two of our societies most significant diseases of aging. Researchers also say that these Ecuadorians have the potential for long life, were it not for their high death rate from alcoholism and accidents. These Ecuadorians have a medical condition referred to as Laron syndrome. This syndrome is the result of a defect in the cell receptors for growth hormone that limits their height to less than four feet.

The New York Times article reporting on these people, titled “Ecuadorean Villagers May Hold Secret to Longevity,” tells us that the gene that causes the growth hormone receptor defect is similar to one researchers have studied in animals such as roundworms. When the roundworm gene is removed, the worms live twice as long as they normally would. This has scientists and drug companies very excited.

This view, that there are genes for this and all of our other characteristics, genes that cause sickness and health, including genes for our mental and emotional life is deeply embedded in our culture and media. The metaphor is something like a string of biochemical dominoes, with a gene at the beginning and some health outcome at the end. Knock the gene over and—click, click, clickety-clack—you live a long time or you get cancer or you have a heart attack or you become a schizophrenic.

From what I’ve been reading lately, this idea of a “gene for” something or other has been more or less abandoned by scientists working in the field of genetics and genomics. One reason for this abandonment is that work has shifted from studying genes to studying DNA molecules and the part they play in recurring biochemical processes. In other words, DNA is just one of many chemicals involved with the recurring chemistry of life.

One of the many discoveries about how DNA works is that many, perhaps even most stretches of DNA associated with a gene occur in more than one place on the genome. This makes functional sense since demand for the protein that a stretch of DNA participates in creating can increase beyond the capacity of a single DNA span to accommodate. So copies exist to help. Each copy is likely to differ from the others. So it now becomes difficult to say exactly where the gene is located.

Instead of a line of dominoes with the gene as the ultimate cause, one scientist has suggested the metaphor of life as music with DNA molecules as one of the instruments in the orchestra. In this metaphor, the music that is life is created by the coordinated effort of all the players and their instruments. And don’t forget the venue: music is profoundly affected by the environment in which it’s played—for its acoustics, for its inspiration of the instrument players, for it’s inspiration of those experiencing the music.

The idea that genes work like the first domino is very attractive. It’s seems simple and direct. People like simple and direct solutions to problems. It gives us some comfort that the people in Ecuador who have Laron syndrome have a simple explanation for their condition that could enable them to live long lives, if they only stopped drinking and stopped acting carelessly. The idea is that in these people’s genes there is a way to extend our lives—and maybe even a way to prevent cancer and diabetes—all by striking the right domino.

The music metaphor seems much messier. If the music isn’t right, it might be an instrument that’s not in tune or an instrument that’s missing or too many instruments of one kind or a combination of instruments that isn’t right for the piece of music being played or too much from one section of the orchestra or maybe even something that’s wrong with the venue.

A few weeks ago, the Journal of Internal Medicine carried an article with the title “Factors Associated with Reaching 90 Years of Age.” The research had many flaws, but what it concluded was that, among a group of men born in 1913, how long a man’s father lived had nothing (statistically speaking) to do with how long the man born in 1913 lived. How long his mother lived had a little bit to do with how long he lived. On the other hand, what had the most significant effect hands down was whether the man smoked. There’s no doubt that DNA is involved in the biochemistry that shortens a smokers life. But do we really need to know what stretch of DNA is at work to know that we should toss smoking and other toxins out of the concert hall?