How we pass our genes to our children

An Oxford-led team of researchers has found out more about what happens during recombination, the process by which the genetic information you inherited from your mother and father is mixed up to make a sex chromosome to pass on to your offspring.

The process of recombination occurs when an individual's chromosomes line up and swap bits of genetic information. In every cell of your body except the sex cells (sperm and eggs), chromosomes exist in pairs, one chromosome of the pair from your father, the other from your mother. At the point when sex cells are made, the chromosomes you inherited from your father and mother line up and exchange pieces of DNA, recombining into a totally new chromosome. This new chromosome gets passed on to your children.

Very few fine details have been known in humans about where these recombinations were likely to occur, and whether there are many recombination 'hotspots': points along the DNA where the two lined-up chromosomes are more likely to exchange genetic information. The research, published in Science, uses sophisticated new statistical methods to produce a much more detailed picture than has previously been available of this variation, and to find many new hotspots.

Dr Gil McVean, Dr Simon Myers, and Professor Peter Donnelly from the Department of Statistics, and their colleagues from the Sanger Institute, near Cambridge, have found that 50% of all recombination events take place in less than 10% of the DNA sequence. They have also discovered that recombination occurs preferentially outside of genes.

'These findings are interesting for a number of reasons,' said Professor Donnelly. 'They shed a new light on the process of human recombination, about which we currently understand rather little. Knowing about recombination is also very helpful in studies to locate the genes whose mutations cause diseases. The higher the recombination rate at a particular point on the genome, the greater the variation there is likely to be at that point, and disease studies will need to examine these areas more closely.'

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