Cas9 Antibody
make sure that there is a rationale for perfecting those techniques in human embryos.” At least, he urges, research- ers and other stakeholders need to have the discussion—after all, however noble the intentions of those who first use the technology, others may use it to drive any application they desire. “Genome-editing platforms are agnos- tic to the gene that you can target and modify,” he notes.
Doudna and her colleagues from
Napa, on the other hand, see value in the basic research possibilities, for instance for the study of mechanisms of DNA repair, and for that reason stop short of calling for an outright mora- torium. Instead, she says, progress should be carefully considered and ap- proved on a case-by-case basis. “Only by doing research will we have the data to make decisions about any potential future applications of the technology.”
Church argues that a de facto mora-
torium already is in place, as research- ers proposing human clinical trials must demonstrate safety and efficacy in culture and animal models first to the satisfaction of bioethics review boards and regulatory agencies.
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It isn’t entirely clear that germline edit- ing with CRISPR/Cas offers compelling advantages for human health beyond existing technologies, such as pre- genetic diagnosis during in vitro fertil- ization. And there remain substantial technical hurdles to overcome even if it does, such as the possibility for off- target or unintended effects. Church (who was a co-author the Doudna article, though he did not attend the Napa meeting) posits the example of a person with two balancing muta- tions. Researchers could conceivably fix one problem with the genome edit- ing technology, only to create another for the patient. In the end, meticulous research would be required to identify and resolve all of these different pos- sibilities.
Church likens the current debate to the 1970s, when scientists grappled
226
with questions surrounding in vitro fertilization. Then, as now, research- ers and ethicists argued over potential pitfalls, and asked whether the payoff for infertile couples was worth the risk. Once Louise Brown, the first “test-tube baby,” was born, the discussion, he says, was flipped on its head. “Now, rather than it being unethical to do any experiments along these lines, it be- came unethical to deprive couples of clinical access to these advanced re- productive technologies.”
Whether genome editing ultimately
achieves a similar milestone is any- body’s guess. But Doudna appreci- ates the comparison. At Napa, she says, one of the attendees observed that “maybe there will be a time when it would be considered unethical not to do [genome editing in the germ line] for certain applications. And everyone said, ‘huh, that’s a different way of thinking about it.’”
In the short-term, the life science
community must come together and decide how best to move forward. A more inclusive follow-up to the Napa meeting is already in the works. “It’s under very active discussion from many parties,” Doudna notes.
References
1. Baltimore, D., et al. 2015. A prudent path forward for genomic engineering and germline gene modification. Science, 348:36-38.
2. Lanphier E., et al. 2015. Don’t edit the human germ line. Nature, 519:410-411.
3. Esvelt, K.M., et al. 2014. Concerning RNA-guided gene drives for the alteration of wild populations. eLife, 17:e03401.
4. Oye, K.A., et al. 2014. Regulating gene drives. Science. 345:626-628.
5. Gantz, V.M. and Bier, E. 2015. The mutagenic chain reaction: A method for converting hetero- zygous to homozygous mutations. Science. 348:442-444.
6. Regalado, A. “Engineering the perfect baby,” MIT Technology Review. March 5, 2015.
7. Niu, Y., et al. 2014. Generation of gene- modified cynomolgus monkey via Cas9/ RNA-mediated gene targeting in one-cell embryos. Cell. 156:836-843.
Written by Jeffrey Perkel, Ph.D.
BioTechniques 58:223-226 (May 2015) doi: 10.2144/000114284
www.BioTechniques.com
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