Researchers at Oregon Health & Science University report that they have created baby monkeys with genetic material from two mothers. Basically, they took the nucleus from one female monkey's egg and installed into the egg of another monkey whose nucleus had been removed. The engineered egg was then fertilized with sperm. The goal of the experiment is to repair genetic defects found in mitochondrial DNA. Mitochondria are the cellular powerhouses that are passed down to progeny only through females. Defects in mitochondrial DNA contribute to a variety of diseases including stunted growth, blindness, mental retardation, and others. As the Washington Post, explains the researchers...
...extracted DNA from the nucleus of monkey eggs; the nucleus contains the genes for most of a creature's traits. The researchers then transplanted that DNA into eggs from other females that had healthy mitochondrial DNA but from which the nuclear DNA had been removed.
They then fertilized the eggs in the laboratory and transferred 15 of the resulting embryos into the wombs of nine females. Two twins were born -- named Mito and Tracker -- along with two other offspring, Spindler and Spindy. So far, all the offspring appear to be healthy.
The really good news is that this treatment, when applied to people, would alter the children's genes so that they would not pass along the genetic defects to their own children.
"We realize this is not just a simple form of gene therapy. This type of gene therapy involves replacing genes in the germline which of course will be transmitted to next generations, which is a concern," [lead researcher Shoukhrat] Mitalipov said. "However, we're talking about patients and birth defects that cause terrible diseases due to these gene mutations. So the only way to prevent these birth defects is to replace these genes."
This is just another step down a road that other researchers have already trod. A similar technique has been shown to work in humans. Back in 2001, Jacques Cohen injected cytoplasm containing mitochondria taken from one woman's egg to the egg of another woman. This technique produced 20 children before the Food and Drug Administration shut it down. Last year, British researchers transferred the nucleus of fertilized human eggs into the enucleated eggs of another woman and let them develop for six days before destroying them.
Unfortunately, this new biotechnical advance has provoked handwringing from the usual cabal of bioconservatives. The Post notes:
Others worried about opening the door to other genetic manipulation. "Unfortunately, we're likely to hear some people saying, 'Okay, we've done this, so why can't we alter the DNA in the nucleus to, say, prevent a predisposition to breast cancer? And if you do it for breast cancer, why can't we do it to weed out a predisposition to baldness?' " said Marcy Darnovsky of the Center for Genetics and Society.
Well, yes. And if repairing or replacing undesirable genes can be done safely, that's a problem, why?
For more discussion on why safe genetic enhancement is ethical, see my column "Human Rights and Human Enhancement."