Scientists eagerly await controversial DNA study
Scientists around the world are anticipating the results of a Chinese study that would mark the first time DNA in a human embryo has been modified in a way that would carry into future generations.
Although the embryos would be for study only and not intended for implantation, the research would mark a significant milestone: the first time human DNA had been altered so substantially that it would change the “germ line” — the eggs or sperm of any child produced from the embryo.
Theoretically that could allow parents in the not- too- distant future to essentially clean their own eggs and sperm of undesired genes — such as ones known to cause cancer — and prevent those genes from being passed on to grandchildren and great- grandchildren.
As scientists debate the practicalities and ethics in journals and online, one expert says he believes the results will land soon.
“There is a paper from China. I don’t think it’s been accepted yet, but I think it will be at some point,” said George Church, a Harvard genetics professor who pioneered genome sequencing in his PhD. He may have some insider insight as well as one of his researchers, Luhan Yang, was poached from Beijing and is thought to have worked on the forthcoming paper.
Genetics research is already improving medicine, for example, informing women if they are more likely to develop breast or ovarian cancer. Scientists can sequence the human genome and parse it, find out where it goes wrong and use that information to prevent, treat and even cure certain diseases, with implications for everything from autism to ALS.
But there’s a big difference between gene therapy — a growing field of largely clinical research that uses genes in treatment — and altering the germ line. That’s because current gene therapies make “somatic” changes to DNA or ones that don’t affect eggs and sperm or embryos.
There are about 2,000 genetherapy studies underway around the world, Church said. One clinical trial is seeking to turn off the genes that make the body susceptible to the HIV virus. Another pending trial out of the University of Alberta seeks to alter genes in men to stop the progression of a degenerative eye disease that leaves sufferers legally blind by middle age.
In terms of changing the germ line, “we are very close,” Church said. “In animal models, you can make animal sperm that has whatever alteration that you want. To say that we’re far away I think would be naive, to embrace it right away without proper testing would also be naive.”
With the medical advancements come concerns of “designer babies” or a 21st- century version of eugenics. “The science is moving much faster than the ethics,” said Kerry Bowman, a bioethicist at the University of Toronto.
Germ- line research “does get into deeper questions of eugenics, especially with spectrum disorders,” he said. “We’ve got to take a deep breath because we’re about to alter the human genetic code in a way that it’s never been altered before.”
In fact, in March, a group of leading biologists called for a worldwide moratorium on such research.
Church said, however, the concern over germ- line therapies is not unlike the fear in the 1970s over test- tube babies. In vitro fertilization is now so common some provinces cover its health- care costs.
It could also be considered a medical evolution. Now genetic testing and even embryo selection could be used to tackle the likes of Tay- Sachs disease and Huntington’s disease, he said.