Scientists at Columbia University have successfully edited the DNA sequences of early human embryos with an accuracy heretofore unseen. This is a breakthrough that could lead to treatments for genetic diseases that are passed from parent to child.
It could also lead to parents being able to choose characteristics in their unborn child that would give it an advantage growing up. They could choose their child's hair and eye color, body type, and other physical characteristics. It's something that is moving from the pages of science fiction movies and novels to laboratories and genetic research facilities. We aren't prepared to deal with the new reality.
The ethical dilemmas are no longer academic exercises. Eugenics is upon us and the scientists are washing their hands of the ethical ramifications,
“As a scientist, you can provide the data for discussion, but then essentially there you stop and let others take over,” said Dieter Egli, the leader of the research at Columbia.
"With a newer technology called base editing, Dr. Egli and his colleagues were able to meticulously replace individual genetic letters in sequences of DNA without causing the damage often observed with an earlier form of gene editing, CRISPR [Clustered Regularly Interspaced Short Palindromic Repeats]," reports the New York Times.
In CRISPR, "a specifically designed sequence of RNA acts as a molecular GPS, matching the exact location of the targeted gene," according to the National Institutes of Health (NIH). Then, "a 'Cas9 Protein' acts as a 'scissor' enzyme that binds to the guide RNA and slices through the DNA strands."
From there, it's a matter of replacing the damaged DNA letter with a healthy one. The problem is that sometimes the scissor slices the wrong segment, or getting the CRISPR machinery to the exact right cells in the human body without triggering an immune response remains a challenge. The Columbia technique is called "base editing," and Egli and his colleagues "were able to meticulously replace individual genetic letters in sequences of DNA without causing the damage often observed with an earlier form of gene editing," according to the Times.
For the new experiments, he and his colleagues set out to alter two genes. One, called PCSK9, can carry mutations that raise levels of LDL in the blood — and the risk of heart disease. The other gene, HBG, directs hemoglobin production in fetuses.
Dr. Egli and his colleagues delivered their base editors into fertilized eggs and into two-cell embryos donated by parents. The researchers didn’t find any of the extensive damage associated with CRISPR.
Instead, the researchers were able to successfully change both the PCSK9 and HBG genes. In some experiments, they simultaneously changed both genes in the same embryo.
But the edits were still not perfect. Sometimes the base editing molecules failed to find their target DNA. As a result, some cells in the embryos retained the original versions of the genes, while others were altered.
In 2018, a Chinese scientist, He Jiankui, used CRISPR to alter the DNA of a human embryo. He said later that his goal was to give children a genetic resistance to HIV. Chinese authorities took a dim view of He's research on living embryos, and put him in prison for three years.
Even this new research is far too experimental to allow clinics and hospitals to use it. But there is a definite way forward, and with this promising line of research, expect other geneticists to seek approval to conduct experiments on embryos.
The Catholic Church strongly opposes using embryos as laboratory material. Current CRISPR research on human embryos routinely results in the destruction of those embryos once the experiment is complete, or involves creating embryos in vitro specifically for research purposes. Catholic teaching holds that human life begins at conception, and that an embryo possesses full human dignity. Therefore, treating an embryo as disposable laboratory material is considered a grave moral wrong.
Nevertheless, the research is moving forward. How ethical and moral concerns are going to play a role in the development of gene editing of human beings remains a fundamental question that needs to be answered before scientists get much farther along in their research.
