An alternative theory to Out of Africa can be found at www.rafonda.com … Ronald Fonda places the origins of Homo sapiens sapiens (modern humans) in northern Eurasia rather than Africa but his arguments are too lengthy to outline here so you will have to read what he says for yourself and make up your own mind.
Having said that northern Asia appears to be the most unlikely habitat on earth for modern humans to evolve. It is very cold to begin with whilst Africa is warm and has a lot of game. I am currently reading a book with the title, 'Digging up the Ice Age: recognising, recording and understanding fossil and archaeological remains found in British quarries' and in this there is good reason to think northern Asia was not always so uninviting, particularly at the timescale envisaged by Fonda. The book is completely uniformitarian in outlook and chronology. However, when they reach Marine Isotope Stage 3 (roughly 60,000 to 30,000 years ago) we find that Britain was part of a vast steppe zone that stretched as far as NE Asia – and it was full of game. Marine Isotope Stage 5 = the last interglacial, known as the Eemian after a river in Holland, is reputed to have been 4 degrees higher than modern British temperatures – yet no evidence of a human presence has been found. They disappeared in the cold period prior to the Eemian and did not return to Marine Isotope Stage 3 (which was not as warm but clearly suited Neanderthals). Around 40,000 years ago modern humans arrived from the direction of northern and central Asia. It is this migration event that Fonda seeks to associate with the spread of modern humans from a northern Eurasian point of origin (sapiens sapiens). He complains there is very little time for modern humans to move out of Africa and reach East and northern Asia prior to 40,000 years ago – and this is a distinct problem as the Out of Africa theory has the initial spread through Arabia and India and into SE Asia and Australia – by 50,000 years ago. Fonda has similar problems as modern humans have to get from up north to down south (Australia) in an equally short space of time. However, most of his arguments revolve around hybridisation and interbreeding between different human groups such as Homo erectus and Homo sapiens etc. In other words, he is not looking for a pristine origin for sapiens sapiens and therefore has a lot more room to manoevre. He is looking at hybridisation as leading to sapiens sapiens rather than trying to find an original Eve (a bottle neck in which emerged modern humans). This leads to the idea that different human groups around the world have different levels of hybridisation – but all have an origin in Homo erectus (who really does seem to have spread Out of Africa and around the world over the course of a million and a half years). The general theory is attractive, especially if Ice Age chronology is exaggerated (using marine isotopes from foraminifera plankton as a chronological marker) as it provides ample room for hybridisation to occur and for humans to move around the world using their feet – but boats should never be underestimated as a vehicle of migration.
What the consensus Out of Africa theory and that of Fonda lack is Catastrophism as a driver of migration. We know there was an event of some kind between 40 and 30,000 years ago, possibly a double whammy event (s). This provides a reason for the migration out of northern and central Asia westwards to Europe and eastwards to East Asia and the Americas, and presumably southwards into SE Asia. However, we also know that humans did migrate out of Africa as the Andaman islanders and tribal groups in India and SEA Asia are testimony of this. The unknown part is when did they move out of Africa and was it as long ago as the Out of Africa theory demands. They may have been set on the move at the same time as the migration in the north – between 40 and 30,000 years ago, representing an entirely different movement but with a common root cause, catastrophic events. Alternatively, and favouring Fonda to a degree, there was also a major event around 70,000 years ago (which involved the eruption of the Mt Toba volcano, possibly not the vector but part of a general upheaval). This would place his 65,000 years ago emergence of sapiens sapiens just after that event – with people migrating northwards and hybridising with locals etc. The best way to view his migration out of northern Asia is to think in terms of one movement among many movements.
The big problem with www.rafonda.com is that a lot of the ideas have not been updated as there have been quite a few articles over the last few years that bring his chronology into question, as well as that of Out of Africa. He is of course correct in his claim the latter is a politically correct theory with an agenda to fit the modern world, formulated by anthropologists fixated by race instead of analysing origins in a clear and unmuddled way. Whatever theory you opt for you are still faced with a problem – if not a fictional Eve in Africa you have to think in terms of an Eve at the inception of Homo erectus – moving the goal posts (but still in Africa).