New techniques in radiocarbon and DNA analysis have made the field of archaeological dating a fast-moving one in which discoveries sometimes destroy long-held assumptions, Tom Higham told a packed talk in Dunedin last night.
The University of Otago graduate is deputy director of the University of Oxford radiocarbon accelerator unit.
Son of Dunedin archaeologist Charles Higham, Prof Higham has been on a nationwide speaking tour, and last night was something of a homecoming.
His main interest is the past 50,000 years, the period in which radiocarbon dating works.
With a half-life of 5500 years, radiocarbon deteriorated fast.
He had been involved in re-dating fossils using ultrafiltration to obtain accurate results.
The human ''family tree'' became ever more complex as the interbreeding was revealed in fossil finds.
''I've often wondered about whether or not someone has a bit of Neanderthal in them.
''Some of my former flatmates are here today . . . the Rugby World Cup's on,'' he joked before the audience in the St David Street lecture theatre at the University of Otago.
Modern humans and Neanderthals intermingled after the humans left Africa about 50,000 years ago in an ''amazing'' diaspora.
It had been their second attempt to leave Africa.
The first time they had not survived.
Today, people outside Africa carry between 1.5% to 2.1% Neanderthal genes.
Associated with Type 2 diabetes, addiction, lupus, and Crohn's disease, Neanderthal genes have been problematic for humans.
However, they also meant better skin and hair.
Humans brought ornamentation, and early artwork, but there was a ''bitter debate'' over the extent to which Neanderthals had engaged in similar behaviour. Some academics believe they started copying humans.
Even less was known about the Denisovan species, the subject of an excavation in Siberia.
They also contributed to modern genes, particularly in Tibetans.
