Discoveries of stone tools in the Arabian Peninsula and India have been found far inland, indicating that humans may have travelled by land rather than by boat. The implements, mainly arrowheads and scrapers, can be dated by the surrounding sand and volcanic ash, most particularly ash from the famous Toba eruption, that has been dated by geologists to 74,000 years ago. Previous genetic research on modern humans that looks at different populations to calculate the length of time to find a common ancestor has dated human migration to as recently as 60,000 years ago.
     Dr Petraglia of Oxford University who led the research team, comprised of colleagues from Australia and India, suggested at the British Science Festival, that the absence of ancient DNA to make additional tests made this area of investigation much less reliable. "I believe that multiple populations came out of Africa in the period between 120,000 and 70,000 years ago," he said. "Our evidence is stone tools that we can date."
     Chris Stringer, from the Natural History Museum, has another explanation for the difference in findings between genetic research and these findings and says, "these tools show that people were in these regions, but the genetic data show an exit from Africa of later than 60,000 years ago. The people in India could have died out."
     Dr Petrgalia, and his team, hope to continue excavation in this region and he says, "We have literally hundreds of projects in Europe and a handful in the Arabian-South Asian belt."

Edited from BBC News (20 September 2010)