Some years ago, I attended a seminar at our university on the ethics of genetic engineering. The panel of experts spoke about the new ability to modify the genes of people with genetic disorders in order to remove the cause of their ailments. Even when they successfully cured the child of an inherited disease, the treatment did not prevent the child from passing on the defective gene to their offspring.
During the Q/A I asked why it was that the children who inherited the disease could be treated and cured with this very expensive treatment but that they did not modify the genes of the parent who had the disease-carrying gene to prevent the disease being passed on to the offspring in the first place. Surely that would be more cost efficient since you would have removed the threat of that disease once and for all in that particular family line.
The ethicists on the panel said that this was a bright line that should not be crossed, that while you could modify the cells of a person, you should not interfere with the germ cells that carry the genetic information to the next generation because then you would be essentially opening the door to creating new types of people and that would be dangerous.
I now learn that that bright line has been crossed. Scientists have been able to create human embryos in which defective mitochondria in a human egg have been replaced with that from a donor. As a result, for the first time, human embryos have effectively three biological parents, inheriting DNA from the mother, father, and donor. The article explains why this was done.
[Mitochondria] are also implicated in a wide range of more common diseases affecting children and adults, such as multiple sclerosis and Parkinson’s disease. Mitochondria have their own DNA and are inherited only from the mother, so replacing defective mitochondria in eggs from mothers who have a high risk of passing on such diseases could spare the children.
The new genetic line will be perpetuated down through the generations and this is what causes ethicists to express alarm.
“That kind of genetic engineering has been ruled off-limits,” says Marcy Darnovsky of the Center for Genetics and Society. “And it’s a very bright line that has been observed by scientists around the world.”
There have been lots of reasons for that line. One big one is purely practical, says Dartmouth bioethicist Ronald Green.
“If we make mistakes, we’ll effectively be introducing a new genetic disease into the human population — for generation after generation,” Green says.
But beyond the risks, Green says taking that step has long raised more far-reaching fears. It’s the kind of technology that could be used to try to create genetically superior humans.
“It could easily move into the realm of gene enhancement,” Green says. “Higher IQ. Improved physical appearance. Athletic ability. That’s a worry to some people — to many people.”
Some of you may have seen the futuristic 1997 film Gattaca. In it, ambitious parents would create several fertilized eggs that would grow to the blastocyst stage and be examined for their genetic potential, and of them select only those with superior qualities to be implanted in the womb. But in that fictional scenario, you could select from just a small set of naturally produced DNA. What is being done here goes well beyond that, to the creation of entirely new genetic lines.