Monkeys hold key to diseases

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GENETIC BREAKTHROUGH

Twin baby monkeys, Mito (left) and Tracker, aged six days. AFP

Four baby monkeys created in a laboratory in the United States could hold the key to the eradication of a class of incurable genetic diseases, scientists revealed on Wednesday.

In an experiment that brings the creation of babies with three biological parents a step closer, Spindler, Spindly and twins Mito and Tracker were born through in-vitro fertilisation (IVF) using a technique that should make it possible to prevent women who carry genetic disorders of the mitochondria from passing them on to their children.

Defects in mitochondria - tiny structures known as the power houses or batteries of a cell because they convert food into energy for the cell - affect about one in 5,000 births and can cause about 50 known diseases, such as fatal liver failure, stroke-like episodes, blindness, muscular dystrophy, diabetes and deafness.

Mitochondrial DNA also plays a role in neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's.

The team of scientists from the Oregon National Primate Research Centre swapped the mitochondrial DNA (mDNA) from the macaque monkey mother's egg for the mDNA of a donor egg.

The reconstructed eggs were then fertilised with the father's sperm and the healthy offspring were born.

Tests showed that no mDNA from the mother's egg had been transferred to the donor egg.

This the first time that primates have been genetically modified in this way.

The fact that healthy offspring have been produced paves the way for the use of the techniques in humans.

But the research, published in the journal Nature on Wednesday, will reignite the ethical debate over genetic engineering and so-called "designer babies".

Babies born using the new technique would inherit most of their genetic material from their mother and father, but a tiny amount - mitochondrial DNA accounts for less than 1 per cent of all the DNA in a human body - would come from the donor of the mDNA. This genetic material would then be passed on to future generations.

Mitochondria, which are strewn throughout the cell body, contain their own DNA separate from that in the nucleus of cells.

Like nuclear DNA, mDNA harbours genes that can mutate and cause disease.

However, mDNA can only be passed on to offspring via mothers' eggs. It is not transmitted by sperm.

Dr Marita Pohlschmidt, director of research at the Muscular Dystrophy Campaign, said: "We welcome these new advances and believe affected families should be offered the choice of having a healthy child." THE GUARDIAN

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From TODAY, World – Friday, 28-Aug-2009

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