About 4500 years ago, part of southern Europe was conquered from the east. The takeover of what is now Spain and Portugal has been revealed by the genes of the people who lived there. The local male line vanished almost overnight, and males from outside became the only ones to leave descendants.

David Reich of Harvard Medical School in Boston, Massachusetts presented the results on Saturday at New Scientist Live in London, UK.

Reich and his colleagues have spent the last few years reading the …