Fragments of ostrich eggs, perforated beads and finely shaped arrowheads have provided the first firm archaeological evidence for the "out of Africa" origins of the world's human population.
Scientists have found stark similarities in the ancient cultural artefacts made and used by Stone Age people who migrated out of Africa and into Asia more than 50,000 years ago.
It is the first time that archaeologists have been able to link African and Indian artefacts so closely together even though they were discovered 3,000 miles apart - suggesting they were made by the same people, albeit of different generations.
Until now the "out of Africa" hypothesis, developed by physical anthropologists and geneticists, has relied almost entirely on the analysis of human skeletal remains or on DNA studies. But a comparative study of Stone Age artefacts found in Africa and India, carried out by Professor Paul Mellars, a Cambridge University archaeologist, has revealed remarkable cultural and technological similarities that suggest a common origin.
The African and Asian artefacts - ostrich eggshell beads, particular types of stones used as arrow- or spearheads and barbs, and a criss-cross art style - are virtually identical despite being found 3,000 miles apart.
It is thought that anatomically modern humans crossed over from Africa to Asia by boat around 55,000 years ago, probably via the Bab el-Mandeb straits at the southern end of the Red Sea. The comparative study suggests a strong degree of cultural continuity during the presumably long human migration from Africa to Asia.
The finds, which were discovered by various archaeologists over many years, come from southern and east Africa and from India and Sri Lanka. However it is the Cambridge University study which has for the first time demonstrated the similarities between the African and Asian material. Most of the African finds date from between 70,000 and 50,000 years ago, while the earliest Indian artefacts discovered so far are just 35,000 years old. Further research is expected to push the Indian dates back further.
Professor Mellars, whose findings are published in the journal Science, said: "We have long suspected that the archaeological evidence for African migration to Asia must exist - and now we seem to have found it."
Prehistorians already know that Homo sapiens left Africa between 50,000 and 60,000 years ago. Eventually, some of these people reached Europe, bringing stone tools with them. We also know there was a similar dispersal east. These people reached Australia, moving along the coast through Arabia, Asia and the Malay peninsula.
The evidence from Australia consists of much simpler tools. Archaeologists presumed there were two separate dispersals, by distinct peoples harbouring different levels of technology. But this contradicts DNA analysis which has found such strong similarities in the genetic make-up of Eurasian peoples that it is difficult to see how they could have come from two or more separate sources.
For the first time, Professor Mellars' study lends credence to that theory by giving it the hard, archaeological evidence it was missing. "It fills out the picture," Professor Mellars said. "Before, the idea of one dispersal was speculation. Now the argument is no longer one just based on the DNA of these people, but on their technology and behaviour as well.
"It is the first time there has been archaeological evidence found and in that sense this is very much the missing link we needed.".
The finds, at Jwalapuram in south-east India and Batadomba-lena in Sri Lanka, show striking resemblances to those from eastern and southern Africa. They include small stone tools that may have been arrow- or spearheads, and carefully shaped and perforated beads manufactured from fragments of ostrich eggshell. A further piece of ostrich eggshell, incised with a distinctive criss-cross motif, has also been found. This would suggest that man could have crossed from Africa via only one dispersal route into Arabia.
The migration route would have split at a later stage, perhaps in eastern Arabia or Iran. Archaeologists will need more evidence before they know where.
Professor Mellars believes the comparatively simple nature of the remains found in Australia can be explained by established patterns that show technology often devolves when humans are continually on the move.
"Up until now, it was felt that the tools found in Australia look so different from those found in Europe that they must have been carried by a separate dispersal," he said. "But what we are finding in Australia could actually be a simplified version of what you get in Africa and India - and Europe. If populations are constantly moving, you would expect some devolution and for the tools to get simpler."
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