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First-ever baby born using ‘three parent’ genetic engineering

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 United States during the 1990s but was banned after fewer than 100 babies were born.


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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.

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.

I had never heard of the three parent technique before. Sounds like a good thing. 

"Birth of ‘3-Parent Baby’ a Success for Controversial Procedure"

Specialists in reproductive medicine say they hope this success will change attitudes toward mitochondrial transfers. They blame in part the term three-parent baby.

That name is misleading and “caustic,” Dr. Grifo said. “It degrades patients who need this,” he added.

“Mitochondria,” Dr. Paulson said, “do not define who you are.” The genes for traits that make up a person’s appearance and other characteristics are carried in the nuclear DNA. If a white woman got mitochondria from an Asian woman, for example, her babies would be white, with no traces of the Asian mitochondrial donor. The ban, said Dr. Paulson, “is not scientific, not rational, not evidence-based.”

Reproductive scientists who have been frustrated by the ban were both gratified by Dr. Zhang’s success and angry that it took so long. Britain recently allowed research on mitochondrial transfers to proceed, but nothing has changed in the United States.


A sperm being injected into an egg during an in vitro fertilization proceduree.Credit Jean-Paul Chassenet /Science Source

That is a great picture, Marlene. 

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