From AFP 04oct01

      A GENE on Chromosome 7 of the 23 human chromosomes plays a key role in the ability to learn language, according to ground-breaking research published.
      A tiny inherited flaw on this gene, called FOXP2, appears to hamper foetal brain development, causing the future child to have speech difficulties that will stay with him all his life.
      The discovery may help to understand how our brain develops the circuitry for speech and how human language itself evolved, the researchers believe.
      "This is the first gene, to our knowledge, to have been implicated in such pathways, and it promises to offer insights into the molecular processes mediating this uniquely human trait," they say.
      The painstaking hunt in the DNA haystack was carried out by a team led by Anthony Monaco at the Wellcome Trust Centre for Human Genetics at the University of Oxford. Their study is published in Nature, the British science weekly.
      About a decade ago, members of the team came upon a large family of several generations of people, half of whom suffered from a speech and language disorder that bore no relation to autism, retardation, deafness or other known causes.
      Those affected had trouble understanding and articulating basic sounds, understanding sentences and using grammar.
      In 1998, the search for the culprit was narrowed down to Chromosome 7, and now - thanks to the discovery of an unrelated person who has the same speech problem - it has been pinned to a single gene, FOXP2.
      Even more remarkable is that just a single flaw in this one gene is to blame for the disorder. In the gene's chemical "ladder," one of the rungs, guanine, is replaced by adenine.
      That one minute alteration has a terrible cascade effect.
      FOXP2 is one of a family of genes which contribute proteins for copying genes into messenger RNA. This is one of the complex processes by which other proteins, the stuff which comprises the body and maintains it, are made.
      The substitution of guanine by adenine subtly alters FOXP2 operations, reducing the amount of "transcription factor" compound for making messenger RNA. That, in turn, has an effect at a critical point in foetal brain development, the Monaco team believe.
      Commentator Steven Pinker, of the Department of Brain and Cognitive Science at Massachusetts Institute of Technology, said the discovery was a "smoking gun" pointing to the cause of this particular language disorder.
      "If FOXP2 really does prove necessary for the development of the human faculty of language and speech, one can imagine unprecedented lines of future research," he said.
      "The first decade of the 21st century may well be thought of as the decade of the gene and the dawn of cognitive genetics."
      Gene-related disorders are one of the most tantalising areas of medical research.
      Doctors hope that by identifying a gene that causes a health problem, they can develop diagnostic tools to prevent parents from handing on that problem to their children.
      More ambitiously, researchers hope to develop medicine that can block the action of a faulty gene, or even replace the flawed gene with the correct one.