Genetics
CRISPR gene drives allow scientists to change sequences of DNA and make that the resulting edited genetic trait is inherited by future generations, opening up the possibility of altering entire species forever. More than anything, the technology has led to questions: How will this new power affect humanity? What are we going to use it to change?
CRISPR genetic engineering now gives scientists the ability to change sequences of DNA and guarantee that the resulting edited genetic trait is inherited by future generations, opening up the possibility of altering entire species forever. More than anything, the technology has led to questions: How will this new power affect humanity? What are we going to use it to change?
At a recent TED talk, Jennifer Kahn questions and shares a potentially powerful application of gene drives: the development of disease-resistant mosquitoes that could knock out malaria and Zika.
Kahn talks about the work of Kevin Esvelt, the scientist behind gene drives. Gene drive systems are capable of altering the traits of wild populations and associated ecosystems.
"It's like a global search and replace, or in science terms, it makes a heterozygous trait homozygous.."
Named for the ability to "drive" themselves and nearby genes through populations of organisms over many generations, these genetic elements can spread even if they reduce the fitness of individual organisms. They do this by ensuring that they will be inherited by most - rather than only half - of offspring. Preferential inheritance can more than offset costs to the organism, permitting rapid spread through the population. CRISPR-based genome editing allows us to build gene drive systems capable of spreading different useful changes, including those that will eventually suppress or eliminate the target population.Related articles
So, what does this mean asks Kahn? For one thing, it means we have a very powerful, but also somewhat alarming new tool. "Up until now, the fact that gene drives didn't work very well was actually kind of a relief. Normally when we mess around with an organism's genes, we make that thing less evolutionarily fit. So biologists can make all the mutant fruit flies they want without worrying about it. If some escape, natural selection just takes care of them."Gene drives might not stay confined to what we call the target species, says Kahn. That's because of gene flow, or species interbreeding. If that happens, it's possible a gene drive could cross over, like Asian carp could infect some other kind of carp. That's not so bad if your drive just promotes a trait, like eye color. In fact, there's a decent chance that we'll see a wave of very weird fruit flies in the near future. But it could be a disaster if your drive is deigned to eliminate the species entirely.
Science journalist Kahn likes to seek out complex stories, with the goal of illuminating their nuances. She teaches in the magazine program at the UC Berkeley Graduate School of Journalism, and is a contributing writer for the New York Times Magazine; she has written features and cover stories for The New Yorker, National Geographic, Outside, Wired and many more.
Her work has appeared in the Best American Science Writing anthology series four times, most recently for the New Yorker story “A Cloud of Smoke,” a story on the complicated death of a policeman after 9/11.
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