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Two large studies of schizophrenia patients have yielded the most convincing evidence yet that the disease can be caused by mistakes in genes. The researchers linked a much higher risk for schizophrenia to three chromosomal regions that are missing chunks of DNA. Although only a tiny fraction of patients carried these particular glitches, similar errors may help explain other cases of the disease. Schizophrenia is a severe mental disorder involving hallucinations and delusions that affects as many as 1 in 100 people; it often runs in families. So far, searches for common genes linked to schizophrenia have been unsuccessful. In...

Really? THE FACTS It is a basic tenet of human biology, taught in grade schools everywhere: Identical twins come from the same fertilized egg and, thus, share identical genetic profiles. But according to new research, though identical twins share very similar genes, identical they are not. The discovery opens a new understanding of why two people who hail from the same embryo can differ in phenotype, as biologists refer to a person’s physical manifestation. The new findings appear in the March issue of The American Journal of Human Genetics, in a study conducted by scientists at the University of Alabama...

Close window Published online: 24 July 2007; | doi:10.1038/news070723-1 New mutations implicated in half of autism casesDisorder linked to genetic differences between parent and offspring.Heidi Ledford Autistic children display a wide range of different symptoms.HENNY ALLIS / SCIENCE PHOTO LIBRARY Half of all cases of male autism may be caused by spontaneous genetic mutations, say researchers who have studied the genetic patterns of the condition. Offspring who inherit such mutations are at a greater risk of having an autistic child themselves. Autistic people have difficulty relating socially with others and tend to focus obsessively on a narrow set of...

Close window Published online: 22 November 2006; | doi:10.1038/news061120-9 Human genome more variable than previously thoughtSurprisingly large segments of DNA found to differ from person to person.Helen Pearson How alike are you and me? About 99.5%Getty Nearly six years after the sequence of the human genome was sketched out, one might assume that researchers had worked out what all that DNA means. But a new investigation has left them wondering just how similar one person's genome is to another's. Geneticists have generally assumed that your string of DNA 'letters' is 99.9% identical to that of your neighbour's, with differences...