Babies with three biological parents could be born disease-free, according to Newcastle University scientists.
Within three years, eliminating human eggs from faulty mitochondria could be used to spare babies from inheriting fatal and incurable diseases.
There are at least 50 known mitochondria diseases including fatal liver failure, blindness, and muscular dystrophy.
The researchers described their experiments in the journal Nature. First, the researchers used modified embryo donated by couples undergoing in vitro fertilization.
The "pronuclei" from the mother's egg and father's sperm was removed and placed into the donor embryo. The genetic material had been removed from the donor egg, except for the part that codes for mitochondrial production.
This technique combined the genetic material from the parents with the mitochondrial DNA of the host — and created a genetically modified (GM), disease-free embryo.
While only eight percent of the modified embryos developed as expected, the scientists would have had better results if they used healthy donor embryos. In the current experiments, any embryos that were alive for six days had to be destroyed to meet British fertility laws. However, if the laws change, the researchers expect the first three-parent baby to be born within three years.
The Times reports:
Professor [Doug] Turnbull said: “What we’ve done is like changing the battery on a laptop. None of the information on the hard drive has been changed. A child would have correctly functioning mitochondria but in every other respect would get all their genetic information from their father and mother.This technique could allow us to prevent the diseases occurring.”
However, messing with life has always been controversial — remember the first test tube baby drama? Now, we've progressed to worries about the creation of GM babies.
Two years ago, Turnbull performed the basic steps of the technique with embryos left over from in vitro fertilization. Last August, other researchers performed a variation of the technique, starting with unfertilized eggs rather than zygotes, on rhesus macaque monkeys.
"It's really interesting stuff," said Oxford neuroscientist Professor Colin Blakemore. "It does indeed take us a step closer to designer babies, as the skeptics warn. But, what's wrong with designing disease out of babies?"
Turnbull still has a ways to go, though: the paper is only a proof-of-concept.
According to The Scientist:
To prove the technique could work in the clinic, scientists would have to try the technique in healthy human embryos -- a task that would be "impossible" due to the associated ethical issues, Jun-Ichi Hayashi of the University of Tsukuba in Japan, who was not involved in the research.