On February 3, 2015, British lawmakers passed a
bill that will allow scientists to make babies from the DNA of three people. Britain is the first country to legalize this
process, and many are hopeful that other countries will soon follow suit, as this
type of embryo modification offers a solution to a particular genetic
problem. Mitochondrial disease is a
disorder in which a person has defective mitochondria as the result of
inheriting a gene mutation from his/her mother.
These organelles are responsible for converting food into usable energy;
without fully functional mitochondria, those affected can experience brain
damage, heart failure, muscle deterioration, and loss of sight. The severity varies greatly among
individuals; some can live relatively normal lives, while others are completely
debilitated or die as a result.
Sharon Bernardi advocates this scientific
breakthrough. She knows too well the
devastation this disease can cause. She
lost all seven of her children to mitochondrial disease, and knows that the
concept of “three person babies” could allow mothers like her to have
biological children with healthy mitochondria.
The technique used is a version of in vitro fertilization in which
babies would receive 0.1% of DNA from the donor woman in order to replace the
mitochondria. The result is a permanent
change in the child’s DNA, and is therefore passed down to future
generations. Altering the mitochondrial
DNA does not change features such as appearance. The mitochondrial exchange can be made at
either the egg or embryo level, as illustrated below:
While this treatment could allow parents to
plan healthy families, there are opponents to this bill, such as Fiona Bruce, a
member of parliament, who claims “there will be no going back for society.” She claims that the implications of the
permanent genetic transformations cannot be predicted as they are passed
through generations. Others argue that approving
this type of genetic manipulation is a step toward “designer babies”, which
would use genetic technologies to modify embryos and choose desirable traits
for the offspring. Rachael Kean, who has
a family history of mitochondrial disease, combats that notion, pointing out
that this bill allows only for the change of mitochondrial DNA (0.01%) and not
the nuclear DNA (99.9%) that “makes you, you.”
Doctor Gillian Lockwood, a reproductive therapist, believes that the
name of this treatment can cause controversy in that it is misleading. She states, “The biggest problem is that this has
been described as three-parent IVF. In fact it is 2.001-parent IVF. Less than a tenth of one per cent of the genome is actually going to be
affected. It is not part of what makes us genetically who we are.”
The Human Fertilisation and
Embryology Authority (HFEA) is expected to grant Newcastle a license to
perform this procedure, the first of which could take place this year. The first “three person baby” could be born
in 2016 and researchers estimate that 150 of these babies could be born each
year.
Posted by Meghan Harrington (Group B)
This was a great post. When I read the title my mind immediately went to the ethics of such a procedure: Could this be used to "optimize" the inherited traits of a child? What are the limitations and qualifications for prospective "three person parents"? Can it only be done for medical reasons or can this procedure be done by those that practice polygamy or polyandry? I am sure it is questions like these that lead to "knee-jerk" reactions against procedures like this. However, much of my skepticism was cleared when you explained that this procedure only allows for the manipulation of mitochondrial DNA. While I think that the "slippery slope" argument is almost always an invalid one, its not unfair to question what the ultimate limitations on procedures like this would be. I am interested how you feel about this topic from an ethics standpoint.
ReplyDeleteEthically, I don't see the harm in exchanging mitochondrial DNA in an embryo. I don't think it's much different than organ transplantation, which has saved countless lives, and this treatment could, too. I also thought of the use of genetic engineering for poly-families or gay couples who all want to make a biological contribution to their child. However, I would probably be more morally opposed to that if it was a matter of recombining nuclear DNA, as that would likely lead to selecting preferable traits. I think in terms of ethics, the motive is most important; if it is a matter of saving a life, I would support it, but if it boils down to families piecing together their genes to create a certain phenotypic outcome, I would have more concerns.
Delete-Posted by Meghan Harrington
This is a very interesting and informative post. I have heard about this reproductive therapy about 2 years ago in a Genetics class. We had discussed that mitochondrial chromosomes do not contribute to the process of meiosis, which is responsible for producing gamete. Mitochondrial DNAs remains consistently unchanged from mothers to children. So in theory, it would be safe to introduce healthy mitochondria into the egg or embryo. I totally support the idea of this "three person babies" treatment. However, I must agree with Dr. Lockwood mentioned above that the name of this treatment is very misleading, which might result to additional debate on this new controversial therapy. Do you know if they have tried this treatment on animal models in labs or was it just a purely in vitro experiment?
ReplyDelete-Posted by Phi Duong
That's a great question. There have been tests done on mice and flies that did not turn out well. However, researchers pointed to the issue of these lab creatures being heavily inbred, which may affect the results. Tests on macaques, though, were not problematic. Human clinical trials will begin soon in Britain now that the UK Parliament has passed this law. (http://qz.com/337701/make-way-for-three-parent-babies/)
Delete-Posted by Meghan Harrington
I found your post to be extremely interesting. I have heard of mitochondrial diseases before, but have never thought to replace the mother's mitochondria with another person's before fertilization before, its brilliant! I do not agree that ethics should stop this procedure from going on. As you have mentioned, it is hardly extreme genetic manipulation. I believe that if someone in the shoes of Sharon Bernardi wanted to have a healthy child without her disease, and we had the scientific means to give her that child, she should have to right to and nobody should be allowed to get in her way.
ReplyDelete-Posted by Ashley Condon