Scientists in the UK have devised a way that could remove the risk that a couple would pass on an incurable genetically heritable illness onto their child. This would involve an alteration of what is typically done for in vitro fertilization. The new technique would produce a healthy child who would actually have three biological parents, instead of two. Genealogists may wonder how to incorporate this child into a standard family tree.
The technique is being called “three -parent IVF”. The technique is being reviewed by the Human Fertilization and Embryology Authority in the UK. At this time, they feel that it is “potentially useful”, and they have called for further research to be done in order to make certain that the treatment is safe and effective.
The purpose of three-parent IVF is to help patients who are at risk of passing on lethal genetic diseases to a potential offspring. Around 200 babies are born with some form of brain, liver, or heart diseases every year. The scientists have identified these conditions as being caused by faults that they inherited from their mother through mitochondrial DNA.
Usually, when a couple chooses to use IVF in order to get pregnant, it involves genetic material from both the woman and the man. Simply put, the woman’s eggs and the man’s sperm are put together outside of the body, in a culture dish, and this is where conception happens. The embryo, or embryos, are then placed into the woman’s womb, and the pregnancy continues from there.
The three-parent IVF could be used in cases where a woman has faulty mitochondrial DNA. Only women can pass on mitochondrial DNA to their children. Men cannot do this. Mitochondrial DNA makes up about 2% of our genetic material, and the rest is “nuclear DNA”. The nuclear DNA is the part that has the instructions about how to build a person. It is passed to a child from both the child’s mother and the child’s father.
Three-person IVF would still involve combining the woman’s egg and the man’s sperm in a culture dish, just like typical IVF. However, before they are combined, the faulty mitochondrial DNA will be removed from the woman’s egg. This would leave the woman’s egg with the woman’s nuclear DNA only.
Now, since you do need mitochondrial DNA in order to make a baby, this is where the third parent comes into the picture. Another woman’s egg would removed from her body, and altered before being combined with the first woman’s egg and the man’s sperm. Her egg would have the nuclear DNA removed, and the non-faulty mitochondrial DNA intact. The sperm and the two altered eggs will all be combined in a culture dish, where conception would occur. Just like with typical IVF, the embryo would then be implanted into the first woman’s womb, where the pregnancy would continue.
Genetically speaking, the child that resulted from this form of IVF would have one biological father and two biological mothers, for a total of three parents.
Image by Jukka Zitting on Flickr