A chimera is an organism which has two or more genetically different groups of cells that originate from different organisms. A hybrid is a being made from the egg of one species and the sperm of another. A mule is a hybrid of a donkey and a horse.

Chimeras of the same species can exist. However, the scientists seek permission to create non-human oocytes. The stem cells they would like to create would be 99.9% human and 0.1% animal. The animal’s egg would have no nucleus, but would contain minute quantities of mitochondrial DNA. The animal’s egg would mix with human nuclei, a chimera oocyte (Oocytes = Eggs whose nuclei have been removed) would be formed and the stem cells harvested after a few days. In other words, imagine using just the shell of, say, a cows’ eggs to hold the human nuclei.

Scientists from Newcastle University, UK, and Kings College, London, UK, want to get cows’ eggs and place human nuclei inside them. They say it is a route for creating stem cell lines. They say this research would help us better understand and cure diseases. It could eventually lead to the creation of organs for transplant. The application has been submitted to the Human Fertilisation and Embryology Authority (HFEA ) for a three-year licence.

This route would free scientists from using donated human eggs.

As it is impossible to carry out experiments on humans, this procedure could be used for this, say the scientists.

Source: Medical News Today (20th November 2006)