Science-Videos

Will Genetics Allow Us to Revive Extinct Species?

A bird that once darkened the skies of the 19th-century U.S. no longer exists, except as well-preserved museum specimens bearing bits of DNA. An ambitious new effort aims to use the latest techniques of genetic manipulation to bring the passenger pigeon back, as North Dakotan Ben Novak, a would-be de-extinction scientist working on the Revive & Restore project at the Long Now Foundation, told the crowd at the TEDxDeExtinction event here on March 15.

"This pigeon flock was a biological storm that was rejuvenating resources and allowing other animals to thrive," Novak said of the storms of Ectopistes migratorius feces that used to fall like rain on the landscape of eastern North America. Plus, with the regrowth of forest on the east coast "there is more passenger pigeon habitat every year."

But if a bird looks like an extinct passenger pigeon, has some of the genetic code of the passenger pigeon, but does not act like a passenger pigeon because it is raised by other breeds and few in number: is it a true passenger pigeon? That is just one of the questions posed by the idea of de-extinction—deliberately resurrecting species killed off by human activity or inactivity. And that question may just challenge one of the fundamental concepts of biology: what determines a distinct species.

Welcome to the new era of the hybrid. Species have always been promiscuous and enjoyed porous boundaries, but synthetic biologists and other scientists seem set to blur those boundaries out of existence.

Geneticist Jennifer Doudna co-invented a groundbreaking new technology for editing genes, called CRISPR-Cas9. The tool allows scientists to make precise edits to DNA strands, which could lead to treatments for genetic diseases ... but could also be used to create so-called "designer babies." Doudna reviews how CRISPR-Cas9 works -- and asks the scientific community to pause and discuss the ethics of this new tool.

Should scientists edit the human genome, striking out undesirable traits like so many typos? “My own views are still forming,” says Jennifer Doudna, who with her research partner, Emmanuelle Charpentier, developed a powerful gene editing technique at her University of California, Berkeley lab several years ago (TED Talk: We can now edit our DNA. But let’s do it wisely). “I’m still trying to get a handle on how and when and why would we want to use this.”

“This” is a genetic editing process that uses an enzyme with the ungainly name of CRISPR-Cas9 to precisely slice into a strand of DNA, snipping out genetic material with the precision of a scalpel. Aside from offering an unexpectedly high level of precision at removing specific As, Ts, Gs and Cs, the CRISPR-Cas9 technique opens a new Pandora’s box: when used on embryos, the genetic changes can be inherited from parent to child.  

Since its invention, the CRISPR-Cas9 technique been used to put lab rats, monkeys, even non-viable human embryos under the genetic knife. But an ethical question hangs over whether the technique should be applied to living human embryos, where an edited gene can be inherited from one generation to the next. One fix could strike out a genetic illness from a family’s bloodline; one mistake could irrevocably alter the human genome in ways we can’t know.

That’s why Doudna, along with a panel of influential genetic scientists, has called for a worldwide pause on any experiment with the human genome. It’s also why she’s helping to convene a three-day summit this December at the National Academy of Sciences in Washington, D.C., where she and others will debate how far the world should take this technology. Doudna hopes the attendees will agree to some framework, any framework, for guiding responsible experimentation.

Gene editing is a polarizing issue, and her informal survey of the research community has turned up wildly divergent opinions. Some researchers favor a complete ban on edits to human embryos, preferring alternative treatments for genetic illnesses (in vitro screening, for instance, that identifies embryos with harmful mutations). Others believe that constraints on research could delay or prevent still-undiscovered cures. Doudna does not expect to solve these differences in three days, but she hopes that the opinions of scientific heavyweights can help shape the conversation. “Highly respected scientists do have a role to play in making a statement that invites people at least to consider their viewpoint,” she says. Bioethicists, lawyers, patient advocacy groups and government regulators will also be there to have their say. If that sounds like an unwieldy conversation, well, it will be. Fortunately, for Doudna, there’s a playbook for this sort of powwow.

Claudia Bagni discusses molecular pathways that are impaired in fragile X syndrome and other conditions, including autism.

UCSC has built the Cancer Genomics Hub (CGHub) for the US National Cancer Institute, designed to hold data for all major NCI projects. To date it has served more than more than 10 petabytes of data to more than 320 research labs. Cancer is exceedingly complex, with thousands of subtypes involving an immense number of different combinations of mutations. The only way we will understand it is to gather together DNA data from many thousands of cancer genomes so that we have the statistical power to distinguish between recurring combinations of mutations that drive cancer progression and "passenger" mutations that occur by random chance. Currently, with the exception of a few international research projects, most cancer genomics research is taking place in research silos, with little opportunity for data sharing. If this trend continues, we lose an incredible opportunity. Soon cancer genome sequencing will be widespread in clinical practice, making it possible in principle to study as many as a million cancer genomes. For these data to also have impact on understanding cancer, we must begin soon to move data into a network of compatible global cloud storage and computing systems, and design mech- anisms that allow genome and clinical data to be used in research with appropriate patient consent.

The Global Alliance for Genomics and Health was created to address this problem. Our Data Working Group is designing the future of large-scale genomics for cancer and other diseases. This is an opportunity we cannot turn away from, but involves both social and technical challenges.