Q&A: Editing human embryos

The research looks at the development of human embryos Credit: PA

Scientists at the Francis Crick Institute have become the first UK-based researchers to be granted a license to genetically modify human embryos.

The move marks a significant turning point for genome editing and fertility research, and has its critics as well as its supporters.

  • What is it that has been licenced exactly?

The team has been given permission to "edit" the genes of human embryos as part of their research into the embryo development.

  • And what is genome editing?

Genome editing is the use of molecular engineering techniques to alter genetic information in organisms.

  • How are they doing this?

The team at the Francis Crick Institute will use a gene-editing technique called CRISPR-Cas9 to to make precise changes to the DNA in early-stage embryos.

The technique allows researcher to edit genes in human embryos Credit: PA

  • Fine, but what is CRISPR-Cas9?

It is a very precise way to "cut and paste" DNA.

Using the system scientists can target specific sections of DNA, delete them, and if necessary, insert new genetic sequences.

  • How does it work?

In its most basic form it uses a small piece of RNA - a genetic molecule closely related to DNA - and an enzyme protein called Cas9.

The RNA component is programmed to latch onto a specific DNA sequence.

Then Cas9 slices through the strands of DNA, like a pair of molecular scissors.

  • Where do the embryos the researcher are using come from?

The embryos are donated by couples undergoing IVF treatment who no longer need them.

Permission to use the technique on human embryos has come from the HFEA Credit: PA

  • Isn't all this a bit controversial?

Yes. Critics say the move could eventually lead to the creation of "designer babies".

  • But there are restrictions on what they can do, right?

Also true. Although the team are allowed to genetically modify human embryos as part of their reserahc, the technique is still restricted.

Under the 2008 Human Fertilisation and Embryology Act, embryos can only be used for basic research, must be destroyed after two weeks, and cannot be implanted in the wombs of women.

  • So is this the first time scientists have been allowed to do this?

No. Last year a group of Chinese scientists became the first to announce they had genetically manipulated human IVF embryos for research.