According to an exclusive report in New Scientist, a breakthrough birth occurred under the radar some five months ago. With the help of John Zhang from the New Hope Fertility Center in New York City, a Jordanian couple conceived and gave birth to a child with more than two genetic parents.
So-called "three parent babies" actually have more like 2.001 parents, according to experts. And the baby boy born earlier this year isn't the first child to have a little more DNA than mom and dad could provide on their own: An IVF technique that relied on small transfers of donor DNA was pioneered in the U.S. during the 1990s, but was banned after fewer than 100 babies were born.
This Jordanian newborn represents the first successful birth in a new wave of "three parent" techniques — ones that are more sophisticated, and that will likely stick around much longer.
For now, there is no country where the method used to conceive the baby boy is explicitly legal. Zhang performed the procedure in Mexico, where, he told New Scientist, "there are no rules."
These techniques involve the transfer of mitochondrial DNA or mtDNA. Often called the "power plants" of the cell, the mitochondria convert energy from food into energy that can power a cell. When someone's mitochondria don't function properly, it's bad news indeed for cells. Mitochondrial diseases can cause a whole host of life-threatening problems, and it's estimated that as many as 4,000 children are born with such conditions in the United States each year. In this case, the couple had experienced four miscarriages and lost two children at young ages to Leigh syndrome, a neurological disorder caused by a mutation in the mother's mitochondrial DNA.
Mitochondrial DNA, which contains just 37 genes compared to the staggering 20,000 or so carried by DNA in a cell's nucleus, comes entirely from the egg cell — the sperm cell contributes no mitochondria to the fertilized embryo, so there's no chance of a father's healthy genes picking up the slack after conception. Replacing the mother's faulty mitochondria with donor mitochondria in the newly conceived embryonic cells can produce a healthy baby while preserving the vast majority of its mother's DNA.
The United Kingdom recently approved a technique where two eggs (one from the mother and one from a donor) are fertilized with the father's sperm. The parents' genetic information is inserted into the donor's embryo, which has had everything but the mitochondria cleared out.
Because the parents who sought Zhang's help are devout Muslims, they didn't want to use a technique where embryos were destroyed. So instead, Zhang used a technique that does the cutting and pasting before fertilization takes place: The nucleus of a mother's egg cell is placed directly into a donor egg, replacing its original nucleus.