Analysis of a small bone excavated at the Denisova Cave in SW Siberia shows that the bone, from a young girl, had DNA from a Denisovan father and a Neanderthal mother. The father came from a population living locally to the Denisova caves while the mother seems to have come from a group living thousands

DNA analyses carried out on samples from the present day inhabitants of Great Britain and Norway give a good indication of the extent to which the two populations mingled during the Viking era. 'Norwegian' DNA varies between 1% in Wales and Ireland to 29% in Orkney and Shetland, areas which the Vikings basically took over. On the

Tibetans are adapted to the low oxygen content at the high (>4000 m) altitudes where they live thanks a lower haemoglobin content in their blood which is again due to a specific gene EPAS1. This gene is more or less restricted to Tibetans, for example it is absent in their neighbours the Han Chinese. But