What exactly happened, the chronology of genes can not suggest, from it is clear only that the genetic diversity of the population suddenly and sharply weakened. According to preliminary calculations, after some catastrophic event in the world remained only 1280 proto-humans who retained the ability to reproduce and passed their genetic material to their descendants. The rest died out for some unknown reason.
The hypothesis says that the surviving people were in some very favourable place for life, surrounded by a harsh world, so they were in no hurry to leave it. About 117 thousand years the ancestors of man lived compactly and interbred among themselves, which eventually led to the emergence of unusual mutations. In particular, a large and developed brain, which became the prerequisite for the emergence of Homo sapiens.
