DNA Swap Could Make Healthier Babies—With Three Genetic Parents

By Eliza Strickland | August 26, 2009 5:30 pm

macaquesThese cute little macaque monkeys may have gotten their fluffy brown fur from their father, their big eyes from their mother, and their good health from… their other mother.

The scientific advance heralded in a new paper in Nature is essentially procedural: Researchers have figured out how to make an embryo that does not carry the mitochondrial DNA of its mother but that of another female instead, which could prevent diseases that are caused by inherited defects in this genetic material. But the study’s immediate impact comes from the ethical questions it raises. “With this you have potentially three genetic parents,” said [bioethics expert] David Magnus…. “This will create the potential for legal and social conflicts.” [Washington Post]. 

While more than 99 percent of an embryo’s DNA comes from the union of a sperm cell with the nucleus inside a female egg, the other 1 percent is found in other structures outside the egg’s nucleus–the mitochondria, the cellular power plants that produce chemical energy. This mitochondrial DNA is inherited only from the mother, but in the new study on rhesus macaques researchers monkeyed with that biological truism.

macaqueThe researchers transferred DNA from the nucleus of one egg into another egg which had had its nucleus removed, without carrying over any mitochondrial DNA in the process — a crucial improvement on existing DNA-transfer techniques. The eggs were then fertilized with sperm and implanted into females, which produced offspring that had mitochondrial DNA from one female and nuclear DNA from another [Nature News]. The four baby monkeys produced by this technique appear to be healthy. Says lead researcher Shoukhrat Mitalipov: “We consider it a big achievement…. Anything we study and achieve in non-human primates can be translated much more easily to humans” [The Times]. 

Defects in mitochondrial DNA can cause a host of disorders, including heart disease in children, blindness, muscle weakness, and movement disorders. Mitalipov says that women who suffer from any of these diseases should be given the chance to have healthy children by editing out their own faulty mitochondrial DNA.

But first, researchers will have to overcome legal obstacles and ethical objections. To test the safety of the procedure in humans, embryos would have to be created solely for research purposes, and it’s illegal to conduct such experiments with funding from the federal government. There’s also a scarcity of women willing to donate their unfertilized eggs to science, as most states outlaw paying for these donations (New York recently became a notable exception). If applied to people, the work would also alter a family’s genes complement in a permanent way that would be passed down for generations, which would violate a long-standing taboo in altering the so-called “germline” because of the potential of unforeseen consequences [Washington Post]. Some experts even wonder if the women who give their healthy mitochondrial DNA could sue for visitation rights to the resultant child.

In an editorial also published in Nature, the journal’s editors write that the public has also rejected the idea of a three-parent union as “unnatural.” Yet similar concerns greeted in vitro fertilization when it was being pioneered in the 1970s, and the technique is now widely accepted. Blanket bans can impede progress and encourage unethical practices. With appropriate oversight, research into other reproductive technologies has the potential to give more couples the chance of having a healthy baby [Nature].

Related Content:
80beats: Is It Ethical to Pay Women to Donate Eggs for Medical Research?
80beats: Did Researchers Really Grow Human Sperm From Stem Cells?
80beats: Controversial Study: Stem Cells Can Provide New Eggs for Infertile Women

Image: Oregon National Primate Research Center at OHSU

CATEGORIZED UNDER: Feature, Health & Medicine
  • Augustus

    “With appropriate oversight, research into other reproductive technologies has the potential to give more couples the chance of having a healthy baby”

    Or they could just adopt.

    Why go to such lengths to add more people to an already overcrowded planet and while so many babies and children have no parents?

  • Dave

    Just another attempt at human perfection. Best not to play god guys, healing the sick is one thing, but seeking perfection would be a severe handicap to humanity.

    Long story short, it’s best to stay away from anything close to A-sexual reproduction (Cloning, Gene manipulation ect), although this may be the opposite of A-sexual reproduction, it poses the same handicap.

  • Jessica O.

    I agree that playing god is nothing but dangerous. Also, if humans did do something like this, how would a custody agreement play out….or even something such as child support? We’re starting to cross the line in certain areas of science – karma guys….it’s gonna come back around and bite us in the behind.

  • YouRang

    I think the only fear we should have is: Would people all pick the same set of genes to pass on? IOW would we be doing the same screw-up with humans that we’ve done with crops?
    In answer to the suggestion to adopt: If OTOH the procedure allowed us to pass on a more highly variable human genome, I’d be for it. IOW not all variability is good; but some of the variability is at worst neutral.

  • farciliptus

    From Augustus:

    “Or they could just adopt.

    Why go to such lengths to add more people to an already overcrowded planet and while so many babies and children have no parents”

    That is too much of a collectivists mentality. For many the idea that the children are a piece of them is an important factor in the fiscal considerations of parenting a child.

    I consider such indignation foolish, but I’m far from the middle ground on human procreation.

    @3: When are we not playing god? I mean with our medicines and surgeries we’re just playing doctor, but the instant we do anything with the basic building blocks we’re playing god all of a sudden?

    Lets be realistic, this is something we do all the time, just people have developed a fear of genetic therapies due to hollywood portrayals of great disasters. That is exactly why they do the science first, then they test it, to be as sure as we can be.

    As far as custody goes, I think that unless the person had an agreement to share custody at the birth the child should have a standard custody, where the birth mother and her husband have full custody.

  • Dave

    you missed the point, farciliptus. Yes i agree we play god a lot, it’s almost a human pastime. My point is, if you want to heal the sick, yes that’s a beautiful thing, but if you want to begin toying with human reproduction beyond helping people get pregnant, you’re leaving bit of space for disaster.

    The basis of male-female reproduction is that many variants of genes are passed on, meaning a vicious bacteria or virus will work on some, but not on others. Even during the black plague, there were survivors of the sickness. But if we advanced on this technology, replacing genes when we pleased, wouldn’t we get to a point where we become so similar genetically that a virus well attuned to a specific cell group could kill a major part of the population?

    Viruses evolve on a scale unsurpassed by more complex creatures, so even if at the point we become a lot alike becomes a success, a mutant strain of a virus could come along to cause disaster. My point is true perfection is false . There’s a line where trying for something more is not needed. This could be a good thing, my only argument is to think about where this is going, that’s all.

  • amphiox

    “The basis of male-female reproduction is that many variants of genes are passed on”

    And this technology is about INCREASING genetic diversity to cure mitochondrial diseases.

    “But if we advanced on this technology, replacing genes when we pleased, wouldn’t we get to a point where we become so similar genetically that a virus well attuned to a specific cell group could kill a major part of the population?”

    This does not follow. Why should the addition of individual choice result inevitably in monocultures? It could just as easily go the other way and lead to an increase in multiple custom genotypes and make the population less vulnerable to viral epidemics.

  • amphiox

    There is no such thing as “playing god”.

    Humans have been manipulating our environment to advance our interests from the very beginning. Without this ability we would not have survived. Genes are just another aspect of that environment, which we have manipulated from the beginning by mate choice.

    What we are doing is “playing man”, not “playing god”.

  • hi

    Sue for visitation rights? Just have them sign something. Problem fixed.

    Interesting developments none the less.

  • Alex F

    We need to speed up our adaptablity and resistance to changes in our world. Ever since we began decreasing our mortalitty, we also allowed defective genes to pass onto new generations. Changes in our world are taking place faster than our ability to evolve to meet them. So we need to take charge of our genetic adaptability. This research will help us meet these challenges. With the excessive introduction of chemical pollutants into our environment over the last few hundred years and their aceleration over the last hundred our bodies are incapable of defending themselves properly. Most of our illnesses come from these contaminents. We need to develop new ways to defend ourselves from them.

  • Chance

    What a shame we let mythical religious beliefs dictate how we save mankind from disease and defects. W/O the religious argument, this would never have been seen as unethical, but rather practical. If you have a high chance to give your child a birth defect, I’m pretty sure 99.9 % of mothers would chose to save their baby.

  • http://discover Teacher

    When will the search for perfecction end? Didn’t the NAZI’s try something like this before?
    What of those people who cannot afford or are ineligible for such transfers–will they form an underclass?

  • Steph S

    It’s so easy to take the high road when something doesn’t affect you directly. Spare a thought for those who have struggled with infertility for years.

    “Or just adopt” – get real. Have you even looked at the logistics of adopting. It can be almost as hard and take as long as struggling to have your own baby.

    I get so fed up with ignorant people who take the moral high ground and are quick to pass judgement on others with things they know very little about.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

80beats

80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles covering the day's most compelling topics.
ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »