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Darrel Falk
 on October 04, 2017

On Reverse Engineering the Human Embryo

Exciting advances in biotechnology present us with difficult ethical questions about the earliest stages of human life.


There has been a second stunning achievement this year in editing human embryos. In August, CRISPR/Cas, a molecular machine that acts like a highly precise pair of scissors, was used to repair a defective paternal gene—one which caused a heart defect. Now, in September, an equally remarkable breakthrough has been published in Nature. Instead of finding and repairing a specified gene, these investigators used CRISPR/Cas to knock out (i.e. mutate) a specific gene to determine its role in embryonic development. Click here to follow the result in a time lapse video (embedded below). The embryo on the right has been injected with a CRISPR/Cas complex specifically engineered to mutate the gene that produces a protein, OCT4. The one on the left is a control (i.e. an unaffected embryo used for comparison). Notice that to begin with the two embryos are indistinguishable. By Day 5, however, the embryo with the disabled gene has faltered badly.

The next video (embedded below) shows how the “gene knockout” was produced. At 20 seconds, a very fine needle is seen coming in from the right piercing the fertilized human egg. Notice the two circles (i.e. nuclei) in the middle of the egg. One contains the genetic information from the sperm, the other has the genes from the egg (At this point, the sperm and egg nuclei have not yet fused.) The tip of the needle pierces each of the two nuclei delivering a tiny bit of CRISPR/Cas. Invisible to the eye, but immediately following the injection, CRISPR/Cas hones in on the OCT4-coding gene and cuts it, thereby knocking out its function. This is precision biology: the diameter of the injecting needle is about one-thousandth the thickness of a dime.

CRISPR/Cas now makes it possible to determine what specific genes (and their products) are doing in the building of an embryo. By deactivating its gene, the investigators “reverse engineered” the function of the OCT4 protein and determined that it acts as a switch. It turns on the activity of certain other genes which, in their activated state, are important in beginning to make parts of the developing embryo.

The details of how this gene works (as well as others like it) help us understand the molecular interactions taking place as it sets up for organ formation, at the very beginning of an embryo’s life. The building of this knowledge base will contribute to relief from human suffering caused by certain diseases. We don’t necessarily know how (or even which) diseases will become treatable, but if the expanding knowledge base of human biology is any indication, it almost certainly will.

Human embryo research is, rightly, a topic which elicits strong reactions from many Christians, ranging from discomfort to dismay. Human embryos are very precious cells. The embryos used in these experiments were all “extras” obtained—with parental permission—from in vitro fertilization clinics. The procedures were carried out in England and were tightly supervised by established government-authorized regulatory bodies.

If implanted into a uterus without these manipulations, many would have developed into full-fledged human beings. They weren’t implanted after the procedures and doing so would have been highly illegal. All died, including the controls. However, if they hadn’t been used for this purpose, they would likely have become non-viable in their storage freezers anyway. In the United States, over 1,000,000 “extra” embryos sit in freezers. Although this work was done in England, it is currently legal in many U.S. states as long as federal government funds are not used.[1][2]

As Christians, respecting the dignity of human life is our sacred calling. It is why we must do all we can to relieve suffering. Our calling extends especially to the disenfranchised, the disabled, the elderly and the not-yet-born. But Christians disagree on how to apply this calling to the complex question of embryonic research.[3] Many Christians examine the human embryo experiments and conclude that manipulation of embryos in such a helpless condition is wrong under all circumstances, no matter what good might seem to come from it. Other Christians, out of a desire to obey the same call for dignity, will look at the same experiments and conclude that it is appropriate and right that human embryos—if they will die in a freezer anyway—be used to gain knowledge that can help relieve suffering.

Regardless of what each of us believes about how best to apply Christian principles to this complicated situation, we must remember that the same principles should guide how we treat each other, even when we profoundly disagree.

About the author

Darrel Falk

Darrel Falk

Darrel Falk is the author of Coming to Peace with Science: Bridging the Worlds Between Faith and Biology and co-author of The Fool and the Heretic: How Two Scientists Moved Beyond Labels to a Christian Dialogue about Creation and Evolution. Most recent is the book, On the (Divine) Origin of our Species. He speaks frequently on the relationship between science and faith at universities and seminaries. From 2009 to 2012, he served as president of BioLogos. Under his leadership, the BioLogos website and daily blog grew to thousands of readers and hundreds of authors, the Biology by the Sea workshop trained Christian biology teachers, and private workshops in New York were a forum for conversation and worship with top evangelical leaders. As president, he brought BioLogos into conversation with Southern Baptist leaders and with Reasons to Believe, and today he continues to be a key member of those dialogues. Falk received his B.Sc. (with Honors) from Simon Fraser University, and earned his Ph.D. from the University of Alberta. He did postdoctoral work at The University of British Columbia and the University of California, Irvine before accepting a faculty position at Syracuse University in New York. Darrel’s early research focused on Drosophila molecular and developmental genetics with funding from the National Institutes of Health and the National Science Foundation. In 1984 he transitioned into Christian higher education, spending most of the subsequent years in the Biology Department at Point Loma Nazarene University in San Diego, where he is now Emeritus Professor of Biology. He is a member of the American Association for the Advancement of Science, the Genetics Society of America, and the American Scientific Affiliation.