A Tipping Point on Human Germline Modification?

Posted by Jessica Cussins March 19, 2015
Biopolitical Times

In a March 5 expose in MIT Technology Review titled "Engineering the Perfect Baby," Antonio Regalado reported on just how close some scientists are to using the precision gene editing technique CRISPR to modify nuclear DNA within human gametes or embryos. A week later, an article in Nature alluded to rumors that this has already been done, and that papers reporting on it will be published shortly.

This startling news has prompted statements about human germline modification from three different groups of scientists so far: one published in Nature, one in Science, and one released by the International Society for Stem Cell Research. All discourage clinical applications and call for public dialogue and debate to acknowledge the profound societal, policy, ethical and safety implications raised by efforts to control the genes we pass on to future generations – a welcome sign from within the scientific community. But the statements offer a range of different paths forward.

A Center for Genetics and Society press statement released this morning supports the call for a moratorium on human germline gene editing. CGS opposes efforts to create genetically altered human beings, and has long advocated that the United States join the 40+ other countries that already prohibit this.

The proposal for the strongest moratorium came from scientists writing in Nature under the clear headline "Don’t edit the human germ line." Their commentary, posted on March 12, calls for "a voluntary moratorium in the scientific community" to discourage human germline modification and to raise public awareness of the critical difference between gene editing in somatic cells and in germ cells. The authors include scientists and executives associated with the gene-editing company Sangamo BioSciences and with the Alliance for Regenerative Medicine, an advocacy organization of stem cell companies and institutes, whose executive committee approved the statement.

The authors emphasize a key distinction between altering somatic (non-reproductive) and germline cells. While somatic gene therapies hold real medical promise for treating a range of diseases, the medical rationale for using germline alterations on gametes or embryos is unconvincing. As the authors of the Nature commentary put it, “Heritable human genetic modifications pose serious risks, and the therapeutic benefits are tenuous.”

(Unfortunately, the authors seem less concerned about “mitochondrial DNA transfer,” which is an example of a distinct, but nonetheless profound, form of germline alteration that poses an accompanying array of inherent challenges. Is there a justifiable reason to condemn every form of germline alteration but this one? Does this really qualify as a “truly compelling case” when safer alternatives exist?)

The second commentary, published today by Science, is authored by a group of prominent bioethicists and scientific figures. As suggested by its title, “A prudent path forward for genomic engineering and germline gene modification,” its tone is more permissive than that of the Nature statement, and in fact it encourages moving ahead with germline gene editing research. It does, however, “strongly discourage…any attempts at germline genome modification for clinical applications in humans, while societal, environmental, and ethical implications of such activity are discussed among scientific and governmental organizations.”

A statement from the International Society for Stem Cell Research, also released today, takes a similar line, calling for “a moratorium on attempts to apply nuclear genome editing of the human germ line in clinical practice.” It notes that

consensus is lacking on what, if any, therapeutic applications of germ line genome modification might be permissible. For example, some argue that the ability to eradicate disease justifies attempts at therapeutic editing of the human germ line, while others emphasize the difficulty of drawing clear distinctions between applications in human disease and attempts at human enhancement.

News articles about these developments have appeared in Nature (1, 2), Science, The New York Times, MIT Technology Review and The Independent. Stem cell biologist Paul Knoepfler has been tracking them on his blog. According to a poll he conducted over the past week, readers across the globe support a moratorium on gene editing of human germ cells.

Science’s Gretchen Vogel sums up the broad calls for restraint here, noting that while these technical possibilities were mostly hypothetical at the infamous 1975 Asilomar conference, we now have to face their reality. Vogel quotes George Church asking: “What is the scenario that we’re actually worried about? That it won’t work well enough? Or that it will work too well?” The fact that both scenarios are deeply troubling marks human germline modification as one of the world’s most dangerous and consequential technologies.

Previously on Biopolitical Times: