A team of 130 of the world’s leading geneticists announced in Science Magazine, they will soon embark on a project that may disturb life as we know it on a molecular level.
In a paper about the team’s epic undertaking, scientists said they hope to build a fully synthetic human genome. Writing an artificial DNA map would open the door to, “growing transplantable human organs; engineering immunity to viruses… engineering cancer resistance into new therapeutic cell lines; and accelerating high-productivity, cost-efficient vaccine and pharmaceutical development using human cells and organoids.”
This is a highly controversial decision, and much of the conversation around it happened behind closed doors without public input. But controversy aside, the new synthetic human genome is on its way, and just a few weeks after the announcement, four of the country’s leading genetic engineers met at a World Science Festival panel to discuss what exactly genetic engineering is, where the current research stands, what types of products they are developing using synthetic genomes, and whether or not a synthetic human genome would one day lead to a synthetic human. (Spoiler alert: They totally want to build an artificial human.)
To start, the scientists discussed how exactly they build something using DNA. First, they order it from the same place you order everything else: the internet. There are several companies that sell DNA, which is mostly harvested from sugarcane, and it is delivered to them via FedEx.
“You can get 2 million pairs for $1,” said George Church, a geneticist at Harvard and one of the leading authors on the Science paper. The DNA comes made to order after a geneticist specifies the base pairs they need, depending on what they intend to do with the delivery.
“If you want it to act like life it has to go into a living cell,” said Pamela Silver, a bioengineer at Harvard Medical School. “You can replace what’s driving the life of that cell with the artificial synthesized piece of DNA and it can take over and allow the cell to grow. If you’re lucky it will boot up.”
The process of designing genetic material, they said, is less like entirely replacing a cell’s current DNA and more like evolving the cell into something new. The housing still has much of its original material inside but now it also contains some new information that will allow it to perform tasks it couldn’t before. In this case, the scientists say success is measured by reproduction. If the cell can read the new DNA it will begin replicating, and each new cell that springs from the modified genetic code will have a DNA pattern identical to the one the scientist created. Then: Voila! You’ve just created synthetic life.
The process, of course, is a lot more difficult than it sounds. It took Craig Venter, the geneticist who pioneered the field of synthetic biology, nearly 15 years of work to make the first successfully self-replicating synthetic bacterial cell in 2010. In Silver’s words, it was an endeavor that “didn’t work the first many times.”
Many researchers in the field have now moved from using bacteria as their starting cell, which only has one chromosome, to working with yeast cells. Synthesizing yeast is more complex since it has multiple chromosomes, but the researchers believe this added complexity will yield more interesting results. One panelist, bioengineer Tom Knight, highlighted how his company Gingko Bioworks has been hired by a perfume manufacturer to help them get around the extremely tedious and expensive task of making rose oil.
“One rose has not very much oil,” Knight said. “It’s not abundant. They grow the roses in Turkey and import them to France and then extract the oil to use in perfumes.” But he believed it would be possible to produce the oil without usingactual roses, so Knight and his company are now experimenting with using yeast cells to create a product that smells like roses.
“The way I think about it is that, fundamentally, biology is a manufacturing technology,” he said. After all, everything you need to know about what makes a rose smell the way it does is inside a rose. All that’s required is to analyze the flower’s genome, identify the parts that code for its signature scent, and then move those parts of the genome into a yeast cell that will replicate quickly and inexpensively.
Ultimately, the process isn’t much different from what yeast does when it ferments barley into beer. The yeast would eat sugar and instead of releasing alcohol and carbon dioxide as a byproduct, as it does for beer, it would release the same chemicals normally found inside a rose. And again, this all may sound simple, but it is infinitely complicated.
“A rose has 200 different chemicals,” says Knight. “Depending on what kind of rose you’re trying to synthesize a scent for you have to get the yeast to make a different mixture of chemicals. So we use different yeast to make different chemicals that will be mixed together to form the correct scent. Eventually we’ll make a version that makes many chemicals at the same time.”
They have not yet succeeded. Knight passed around some samples of the rose yeast they have made so far and the scientists all agreed: “It smells like yeast.”
At one point during the panel, moderator and journalist Robert Krulwich wondered about the ethical concerns of evolving an organism to behave in a way that it wasn’t naturally built to behave. “Yeast are in the bread and brewing business and we don’t know what they’d think about being in the rose business. Do you worry that you’re the disturbing the yeast in some sentient way?” he asked.
The panelists countered by saying that type of concern will be legitimate once they are engineering larger organisms. Right now they don’t really see themselves as working with “life” in the way most people would define it. In the end, they are all just engineers manipulating structures, and according to Stanford synthetic biologist Drew Endy, “The word creation has a lot of implications. As an engineer I’m not familiar with them—unlimited budget, a perfect understanding of the material, and absolute power. That’s not what I experience. I have a limited budget and capacity to deploy my intentions. I grew up as a civil engineer. We know enough about gravity to make a suspension bridge. But we’re still using gravity wave detectors to understand gravity.”
The synthetic organisms they’re creating, Endy said, are less like a new form of life and more like a new type of language, “The way the DNA is being read out has been changed. The expression of it has been changed.” But the yeast is still yeast.
The ethical questions become much more difficult to answer when a synthetically built cell propagates enough to grow a human (or any animal for that matter). If these researchers are identifying themselves as engineers and not biologists—or even as the creators of life—how do we feel about their proposal to build an artificial genome? As the panel was wrapping up, Krulwich asked them about the controversial project highlighted in Science Magazine.
According to Endy, there are questions that humanity will have to ask itself first before moving forward: “Under what conditions would I wish to synthesize the next generations of human beings?” he asked. “There’s gonna be a plurality of positions and opposition, but it’s something I can imagine and I believe it’s totally doable. It’s worth having conversations about.”
Based on the fact that science can’t make yeast smell like a rose, it’s pretty clear it will be a long time before we have a race of synthetically-built humans marching through the streets demonstrating for their civil rights. But when that day comes, these are the biological engineers who will have been responsible for creating them. Krulwich asked each member of the panel to raise their hands if they believed science should one day build a human using an artificial genome. They all put their hands in the air.
Article Credit: Good