Ed had a great note this week about a group of Harvard scientists using CRISPR, the revolutionary new gene-editing technology, to enable pigs to harvest donor organs for humans. (A Chinese team recently used a CRISPR-like technique to engineer “micropigs” to sell as pets.) Ed’s note reminded me of a fascinating episode of Radiolab from the summer that profiled CRISPR’s creators. You should really check out it if you haven’t already:
If you don’t have time, below are the basics, summarized for us by Ethan Zuckerman:
CRISPR makes it vastly easier to cut the DNA within an organism, which allows biologists to remove genes they don’t want and add genes they do. (Turns out that the cutting is the hard part: DNA’s self-repair mechanisms mean you can introduce sequences you’d like incorporated within DNA, and the cell’s DNA-patching systems will include your sequence as a patch.)
By itself, CRISPR is provoking lots of thought about what sorts of genetic manipulation are appropriate and desirable. But a further idea—the gene drive—is leading to impassioned debate within the scientific world.
It’s possible to make CRISPR inheritable, which means that not only can you change the genome in an organism, but you can make it virtually certain that its offspring will inherit the genomic change. (Inherited changes generally propagate slowly through a population, as only half the offspring inherit the change. But if you make a change on one half the chromosome and put CRISPR on the other half, the offspring either inherits the changed gene, or CRISPR, which will then make the change.) The upshot is that it could well be possible to engineer a species of mosquitoes that couldn’t pass on malaria, or that simply couldn’t reproduce, ending the species as a whole.
Maria Konnikova also touched on CRISPR for her Atlantic piece on “brain hacking”:
[O]ne can imagine a day when we are able to identify genes associated with cognitive ability and manipulate them for higher output. Granted, that day is a long way off. “There’s no single gene for intelligence. We can’t just go in and change one gene and become cognitively enhanced,” [MIT neuroscientist Guoping Feng] says. What we can do now is gain a deeper knowledge of the relationship between the genome and brain function—and perhaps in a few decades, we’ll be in a position to evaluate whether such tinkering is a good idea.
When that day comes, health concerns may overshadow the ethical considerations around engineering supersmart babies. The truth is that we have no idea what the long-term effects of any artificial enhancement may be. Will our brains be able to withstand running at artificially heightened capacity? “There’s a discussion going on that our brains have evolved over millions of years and might already be at optimal neurochemical equilibrium, and any attempt to change something there can only do harm and can’t strongly enhance brain function,” Martin Dresler, a German neuroscientist who studies cognitive enhancement, told me. If that’s the case, ethics could be the least of our worries.