MRT: Method One- Pronuclear Transfer
In the adjoining image, the zygote has a defective mitochondrion so MRT therapy becomes necessary in a situation like this. Ideally, we would have transferred a healthy mitochondrion from another woman and removed the defective mitochondria. But we do not have the technology for this process. So, we remove the pronucleus from the zygote and insert it into a donor female’s (who has a healthy mitochondrion with its nucleus removed) egg cell. This step is called as Pronuclear Transfer as we transferred the Pronucleus from the unhealthy zygote to a healthy egg cell of the donor. This is one way, how MRT therapy works. MRT therapy is also called three parents’ baby because the mitochondrion of the donor has some donor DNA and as a result, the baby formed would have DNA from 3 sources: nucleus and chromosomes from mother and father and mitochondrial DNA from the donor. Do note that since pronuclear formation is happening, this step happens after the fertilisation of the egg by the sperm.
