If you have read a lot of newspapers and news magazines in your life, you must have noticed that they seem to contain the same old story regardless of era — the headlines of coups d’etat, assassinations, wars, invasions, sections on famous marriages, divorces, births and deaths, corporations rising and falling, films and celebrities in fashion etc. But sometimes, you notice a new kind of story happening, a new trend in the human narrative. Just like when business news was largely dominated by manufacturing until Bill Gates changed that. Without the digital age, there would be no Wired magazine and no online news. These may be the unusual stories which are few but that turn out to define a generation, or even a new way of telling the news.
Imagine DNA as the news of life. It is the code of life. It is told inside living organisms. At this point, scientists are now studying which paragraphs tell stories and if they don’t (what they call “junk DNA” which is the vast majority of DNA just like joke about the content of newspapers in general) what they are there for. We have already mapped the human genome and a running list of other organisms. Knowing the genome of something is like holding a newspaper with all the letters without really knowing which form paragraphs that in turn tell certain stories, and maybe how connected these stories are.
We share the “news” with all living organisms. It is when some little thing changes in the letters that the stories become another kind of news, another kind of organism. We humans each have about three billion “letters” (A,T, C and G) that are supposed to tell our biological news. However, only 45 million of these letters form genes that code for proteins — those so-called “building blocks” of life. The rest used to be called “junk DNA” because then, it was not apparent to the scientists what their role was. But soon enough, scientists have noticed that what they previously junked as “junk” is turning out to be essential in telling your biological story as well. Fundamental as they may sound, the “building blocks” seem to depend on the 2.955 billion “junk” DNA to wake them up, drive them to work, or even put them to sleep.
Katherine S. Pollard of the University of California San Francisco has been scouring the “news” between chimps and humans. Six years ago, she was part of the team that compared the genome of a human and a chimp. They found that since we shared a common ancestor with the chimp six million years ago, only 15 million letters of our three billion-letter genome changed. This makes us only less than one percent genetically different from the chimpanzee. In her article in the May 2009 issue of the Scientific American entitled “What Makes Us Human?” she brings us further to the more intimate stories that lurk inside that one percent difference to further reveal to us what makes us human.
She made a computer program to find the stretches of letters that changed the most since the split with chimps. On top of her list were 118 letters which they called HAR1 (Human Accelerated Region 1). These letters do not code for protein so that a few years ago, they would have been dismissed as “junk DNA.” But it turns out that the letters of HAR1 are responsible for the development of the cerebral cortex and possibly, the production of sperm. The cerebral cortex, that which houses your logical and planning functions, is especially large in humans. This is the one which a recent study showed as being especially thick in smart humans.
Hey guys, this is the ultimate reality show — discovering the genetic stories that define our biology as humans. It could be a puzzling and frustrating idea to ponder. For instance, whenever I accidentally come cross a wrestling program on TV, it makes me really think whether we have evolved far from since we shared an ancestor with chimpanzees. It did not help that I also was recently made aware of the Thumb Wrestling Federation. But irony of ironies, Pollard’s article revealed that the “junk DNA” responsible for development of the wrist and thumb is one of the fastest-changing regions in our genome as well — helping to define what makes us human. Our ability to make use of our wrist and thumbs has enabled us to develop many tools and gadgets. Mobile phone manufacturers ought to put up a shrine to the DNA sequence (named HAR2) responsible for this.
Other “junk” DNA sequences have also been discovered like the one that facilitates modern human speech, the digestive tolerance for starch, milk, and one that controls brain size.
So next time you read a newspaper, think of your own story — the story of your biology unfolding inside of you. It contains the same general story we share in common with all life since it began 3.8 billion years ago. But it also has a few sections that carry breaking news. Those sections, though relatively few, are the ones that make you wrestle with your thumbs and your mobile phones. They are, for better or worse, what makes you human.
* * *
For comments, e-mail dererumnaturastar@hotmail.com