I owe an apology to my genes. For years I offhandedly blamed them for certain personal defects conventionally associated with one’s hereditary starter pack—my Graves’ autoimmune disease, or my hair, which looks like the fibres left behind on the rim of an aspirin bottle after the cotton ball has been removed, only wispier.
The map just got lost
Illustration by Jayachandran / Mint
Now it turns out that genes, per se, are simply too feeble to accept responsibility for much of anything. By the traditional definition, genes are those line-ups of DNA letters that serve as instructions for piecing together the body’s proteins, and, I’m sorry, but the closer we look, the less instructive they seem—less a “blueprint for life” than one of those disappointing two-page Basic Setup booklets that come with your computer, tell you where to plug it in and then direct you to a website for more information.
Scientists have learnt that the canonical “genes” account for an embarrassingly tiny part of the human genome: Maybe 1% of the three billion paired sub-units of DNA that are stuffed into nearly every cell of the body qualify as indisputable protein codes. Scientists are also learning that many of the gene-free regions of our DNA are far more loquacious than previously believed, far more willing to express themselves in ways that have nothing to do with protein manufacture.
Blueprint in ‘excess baggage’
In fact, I can’t even make the easy linguistic transition from blaming my genes to blaming my whole DNA, because it’s not just about DNA anymore. It’s also about DNA’s chemical cousin, RNA, doing complicated things it wasn’t supposed to do. Not long ago, RNA was seen as a bureaucrat, the middle molecule between a gene and a protein, as exemplified by the tidy aphorism “DNA makes RNA makes protein”. Now, we find cases of short clips of RNA acting like DNA, transmitting genetic secrets to the next generation directly, without bothering to ask permission. We find cases of RNA acting like a protein, catalysing chemical reactions, pushing other molecules around or tearing them down. RNA is like the US vice-presidency: it’s executive, it’s legislative, it’s furtive.
For many scientists, the increasingly baroque portrait of the genome that their latest research has revealed, along with the muddying of molecular categories, is to be expected. “It’s the normal process of doing science,” says Jonathan R. Beckwith of Harvard Medical School. “You start off simple and you develop complexity.”
Nor are researchers disturbed by any linguistic turbulence that may arise, any confusion over what they mean when they talk about genes.