All you need to know about hybrid embryos

WHAT IS A HYBRID EMBRYO?

A hybrid embryo is the fusion of human and animal material to create a new type of cell.

British scientists want to create a specific type of embryo, called cytoplasmic, which uses “empty” eggs from rabbits or cows and has genetic material from human donors inserted into them. The research sees the transferring of nuclei containing DNA from human cells, such as skin cells, to animal eggs that have had almost all their genetic information removed. The resulting embryos are more than 99% human, with a tiny animal component making up around 0.1%. This animal DNA remains in the mitochondria, which are tiny rod-like power plants that sit outside the nucleus and supply energy.

Stem cells, which have the potential to become different kinds of tissue, are then grown in the laboratory from these embryos.

These stem cells contain even less of the animal genetic material, making them practically 100% human, scientists have argued.

WHY IS IT CONTROVERSIAL?

Some religious and pro-life groups disagree with creating embryos only to see them destroyed once the research is over (the plan is for them to be destroyed after 14 days). Embryos are the start of human life, meaning the issue is particularly sensitive. Other people fundamentally disagree with mixing human and animal material, saying it is ethically wrong.

WHAT DO SCIENTISTS THINK?

At present, scientists have to rely on human eggs left over from fertility treatment, but they are in short supply and are not always good quality.

Scientists around Britain widely believe that research into diseases like Parkinson’s and Alzheimer’s is being hampered by lack of eggs.

Two teams, from King’s College London and Newcastle University, have applications pending with the Human Fertilisation and Embryology Authority (HFEA) to start research with animal-human embryos.

WHAT ABOUT THE LAW?

In May, the Government published the Human Tissue and Embryos Bill, which followed on from a white paper just a few months earlier.

The white paper proposed a complete ban on creating human-animal embryos, although the Government argued there was some scope for this to alter. There was outrage among the scientific community, which opposed the ban and said embryos were needed.

The House of Commons Science and Technology Committee found the creation of hybrid and chimera embryos was necessary for research and there should not be a complete ban.

The bill sets out provisions for a regulation-making power to allow exceptions to a total ban.