A mother’s eggs need to be as free as possible from genetic defects to maximise the chances of producing a healthy baby. Nature selects her best eggs from an early stage – most are discarded even before she is born. Immature eggs in the developing female foetus have special ‘jumping genes’ that behave like viruses, moving around and causing genetic mutations. Scientists think that eggs susceptible to mutations are purged, so that only those of the highest quality remain. In an experiment on mice, a drug used to treat AIDS, called AZT, was found to inhibit the most active jumping genes. Pictured is the ovary of a mouse foetus with eggs, stained green, protected from dying by AZT. The discovery raises the possibility that the number and quality of immature eggs might be enhanced by drug treatment.
Written by Mick Warwicker
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