The paper, by biotech’s enfant terrible Craig Venter, is titled “Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome.” Much of the popular media, which seems to now be primed to explode into hyperbole every time it sights a Venter paper on the horizon, translated this piece of news to read that researchers had “created artificial life.”
But I don’t really blame the journos for indulging in sensationalism. Artificial life, or anything that vaguely even sniffs of it, has always been sensational. Ground zero for this topic may well have been in 1819 when Mary Shelley published her blockbuster novel Frankenstein and unintentionally (I’m sure) spawned a whole new genre that lamentably blended fiction with bad science.
In Shelley’s opus, her hero Victor Frankenstein is an expert in galvanism, a technique in which a chemical reaction triggers an electric current that in turn powers a biological activity – like stimulating a muscle spasm. Victor uses it to jolt life into a non-living “object,” a patchwork frame of bones and other anatomical detritus that he has pilfered from morgues and slaughter-houses and cobbled together into an 8 foot monster. Victor cranks the current, the monster comes to life, and the rest becomes cinematic history.
The hero of last week’s news, Craig Venter, is an expert in sequencing and synthesizing DNA. He has now successfully manufactured the entire genome (DNA) of a bacteria X in the lab and then inserted it into bacterial cell Y (from a closely-related species) that had been stripped of its own DNA.
A cell without its DNA is pretty much a lifeless shell; although all essential infrastructure is intact, there’s no instruction manual telling it what to do. So what happened next is what you would expect: the new lab-made DNA behaved pretty much like the natural DNA it replaced.
It “re-booted” the cell, which started going about its daily business as dictated by this new DNA. And eventually, this transplanted cell gave rise to new cells that made all the proteins and cellular components as per the instructions contained within DNA X.
The journos called this feat the creation of artificial life. Venter himself calls this DNA-transplanted cell and its daughters ‘synthetic’ because they are “the first self-replicating species we’ve had on the planet whose parent is a computer.”
The genome that he started with to make a copy: natural. The cell that he put the copied genome into: natural. This cell’s progeny: all natural except for the synthetic genome, which you can argue is also almost natural because it still carries the almost intact blueprint of a natural, existing organism.
So, although “self-replicating species…whose parent is a computer” is a great sound-bite, that’s all it is. The only way I’d buy it is if Venter had put his synthetic genome into a synthetic cell that had also been parented by a computer. And the genome itself, after all, wasn’t made from scratch – i.e., custom-designed – to make the bacteria do anything different or new. It’s a copy of an existing genome (with a few dangerous genes left out) that worked just as well as the original when plonked inside a foreign cell.
I agree with David Baltimore, a Nobelist, who told the NYTimes he has “not created life, only mimicked it.” But for Venter, however, “It’s certainly changed my views of definitions of life and of how life works,” as he said in an interview with Science magazine, which published his paper.
Creating artificial life is a very real goal and the raison d’etre of synthetic biologists—people who want to design and construct new biological systems or organisms with novel biological functions not found in nature, ostensibly for a greater good.
In my non-expert eyes, this has already been done to an admirable extent way back in 2003. That’s when Jay Keasling, a scientist from UC Berkeley, published a paper that described how his team had constructed a kind of yeast that could churn out the malarial drug artemisinin, a compound that’s produced only in a particular plant.
To do this, the team had to cobble together genes from several different organisms to custom-build a package of DNA, then construct a previously non-existent metabolic pathway in yeast that converted yeast cells into anti-malarial drug factories.
Others are pushing the boundaries of creating artificial life even further. There are plans afoot to create life that resembles the form with which it emerged from the primordial soup – when the primary ingredient was not DNA, but it’s chemical cousin, RNA. Unlike DNA, RNA has properties that in principle allow it to act both as genetic blueprint and a mechanism for cellular self-assembly.
Nobody disputes that Venter’s work is a technological marvel that makes it much easier now to engineer large genomes. It took a lot of fancy footwork in the lab to piece together a complete genome that’s about a million bases (the DNA “letters” A, T, G, C) long, get that sucker into a cell without letting it get destroyed by the cell’s internal defense system, and then get that cell to replicate.
I understand that this was a proof-of-principle experiment to show that a lab-made genome can direct a cell into replicating itself. But for the $40 million price tag—pretty pricey for a pilot experiment, and incidentally the same amount that Keasling got from the Gates Foundation to industrially scale up his malaria drug-producing yeast—I wish that Venter had synthesized a genome that did something useful. A genome that included instructions for bacterial cells to slurp up oil, for example, might have come in handy.
Gibson, D., Glass, J., Lartigue, C., Noskov, V., Chuang, R., Algire, M., Benders, G., Montague, M., Ma, L., Moodie, M., Merryman, C., Vashee, S., Krishnakumar, R., Assad-Garcia, N., Andrews-Pfannkoch, C., Denisova, E., Young, L., Qi, Z., Segall-Shapiro, T., Calvey, C., Parmar, P., Hutchison, C., Smith, H., & Venter, J. (2010). Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome Science DOI: 10.1126/science.1190719