Babies with three parents to be born in UK

The first baby was born with three parents last year. Two Mums and a Dad to be precise. The baby boy, now five months old, lives in China. But, new UK law means we too will be having three parent families as soon as 2017. The point of this? To let parents not pass on their genetic disease to their kids.

DNA makes us who we are. You know the spiel. DNA sits in the nucleus and when the body wants to heal or make something new, it wanders down to the nucleus, drags out the blueprints (DNA) and gets making. But sometimes the blueprints have mistakes. This is when we get certain diseases or abnormalities. We call them genetic diseases because they are caused by faulty genes in DNA. With three parent babies we can remove the chance of getting these diseases by cutting out the bad DNA and replacing it with the healthy DNA of a third parent. Basically, giving the baby the best of a bunch of three.

I was lying a bit when i said DNA sits in the nucleus. A little bit lives in mitochondria. Yup. An organelle. They don’t just make useful energy from your food. They also have a contain a small amount of DNA. This, just like the DNA in your nuclei, gets passed onto baby. And this is the DNA we can protect our three parent babies from.

Half our DNA comes from the nucleus of our mother’s egg. Half from the nucleus of our father’s sperm. So where does mitochondrial DNA fit in? In an egg, mitochondria float around pretty much like they do in most cells. But in a sperm the mitochondria crowd into the base of the tail to give it the energy to swim. Because the tail falls off when entering the egg, we don’t get mitochondria from our fathers, only our mothers. This is why we have only explored the possibility of two mums and one dad. If Mum has a disease caused by bad genes in her mitochondrial DNA, we take the good nucleus DNA out of her egg and place it inside Mum number twos egg with healthy mitochondrial DNA.

Voila! A healthy egg made from the DNA of two mothers ready to be inseminated with sperm. The process of meiosis can begin making a baby!