There are 3 billion base pairs in human DNA. Each is a rung on the latter of the double helix structure. But it is not as though each rung is a gene. Instead, a collection of them will define a single gene, of which there are over 20,000. The feat of mapping them all was accomplished in 2000. “Today we are learning the language in which God created life," President Clinton said at a White House ceremony celebrating the deed, reported in the New York Times. It is both an echo and update of Galileo’s quote from long ago: “Mathematics is the language in which God has written the universe.” It may be that Clinton’s statement was said for expediency, as Galileo’s certainly was not—the latter meant it. But I like when people are respectful toward God.
At about the same time, beginning with single-celled organisms like bacteria, other researchers were finding identical segments of DNA that didn’t seem to do anything and were interspersed among the segments that did. Says the above New York Times article: “. . . human DNA is full of repetitive sequences—the same run of letters repeated over and over again—and these repetitions baffle the computer algorithms set to assemble the pieces.”
Sean Carroll, in his 2007 book, The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution, incorrectly called these sequences ‘fossil DNA,’ though he surely knows what they are by now. At almost the exact time of his book’s writing, that DNA was being revealed as anything but ‘fossil.’
Things must be given a snappy acronym for memory’s sake. CRISPR did the trick: “clustered regularly interspersed short palindromic (reads the same backward and forward) repeats.” Now—just what were they, those repetitions that would “baffle the computer algorithms?”
One researcher ran the middle sections of such repeats through a database. He found that they were exactly the same as the DNA segments of attacking viruses!—as though the host ‘remembered’ its attacker. Walter Isaacson uses the analogy of copying and pasting a mug shot. That way, should that virus ever show its ugly mug again, it will immediately be spotted. Without fail it will be spotted, since the mug shot is not just there once at the post office, but interspersed again and again throughout all the DNA corridors!
Adjacent to these clustered regularly interspersed short palindromic repeats (CRISPRs) are enzymes* that not only do the copy and paste, but also the search and destroy. They’ve been dubbed ‘CRISPR-associated enzymes’—‘Cas enzymes’ for short. Since there are several of them, and they all perform different functions, they are numbered: Cas1, Cas2, and so forth.
*Enzymes are proteins that initiate chemical reactions but are not consumed themselves. The Cas enzymes molest an invading virus, one targeting it, one holding it down, one cutting it up into harmless bits, one posting the mug shot for future reference. What all this means, and this with the Cas enzymes only in 2008, is the structure and mechanism of the immune system is revealed!
Now, before progressing to what is annoying, let’s stop and savor the accomplishment, for it is monumental. You don’t have to right away reveal yourself an old codger forever posting signs ‘No turn-arounds in this driveway!!’ It’s proper to savor the accomplishment first. That’s what ‘The Code Breakers’ does, subtitled ‘the Future of the Human Race,’ the Walter Isaacson book completed in 2021. Isaacson has make it his specialty to write biographies of the world’s memorable innovators—even geniuses—such as Leonardo DaVinci, Albert Einstein, Ben Franklin, Steve Jobs, and just now, Elon Musk. The Code Breakers is more of a collaborative story. The names are not as recognizable. Isaacson wrote a similar book on the digital revolution in which most names are not as recognizable. Jennifer Doubna is the main focus of The Code Breakers. She is not the one who gave CRISPR its name, though. That fellow is Francisco Mojica.
It’s all very proper to name names when relating a human play, and Isaacson’s book is a must-read for anyone wishing to be brought up to speed on the topic. Only the Watchtower does not name names, and that is because it is a superhuman play that they follow and relate. You don’t have to know the names of the actors to follow the play; it can even be a distraction if you do. Besides—it is a bit of a self-reinforcing cycle—because they’re not following the human actors, but the play itself, they don’t always know just who the actors are. With just mild exaggeration, Elon Musk reduces to ‘one wealthy businessman,’ Vladimir Putin to ‘one Russian politician.’
But that’s an aside. Isaacson is telling a human story, and he does relate the names and the interplay between them. For an interesting read, you must relate the names. Besides, it’s risky if you don’t. There is no sweeter sound to a person than the sound of his own name. “Libraries and museums owe their richest collections to men who cannot bear to think that their names might perish from the memory of the race,” writes Dale Carnegie in How to Win Friends and Influence People, a book that is largely forgotten today but shouldn’t be. His observation is true enough. I can’t walk though a park without passing benches emblazoned with the names of those contributing to it.
But that’s another aside. The works of the code-breakers are truly momentous. Name them all—not a problem with that. Now—on to what is aggravating:
To be continued:
****** The bookstore