I remember when I was talking to my professors many years back about the origin of the human species, most frown upon the idea that the human species had one single original from a specific cradle in Africa. Similarly, I don't believe life begun in a single pond and took over like a wild weed. In all likelihood, all species have had multiple origins and through merging, interaction and competition managed to output the varieties we see today. Some survived and some vanished permanently leaving traces of their existence in other species.
As more and more new evidence piles up in regards to the origin of the human species the time table seems to also drift back further and further in time. This is the first evidence that no single cradle has produced humans. Rather a nursery must have developed and most likely from the interaction of other hominid species over long periods of time.
To support this hypothesis we have the recently discovered bones of a young boy from South Africa. His existence challenges the idea that humans only emerged just 180,000 years ago (somewhere around Omo Kibish in Ethiopia). I have always used 350,000 years as the metric for the existence of the human species even if many anthropologists disagree with the premise. As of recently, the fossil evidence seems to find me in agreement with sciencentis from South Africa and Sweden about the time span and origin of the human species. This finding of the boy from South Africa also rhymes with earlier artefacts founds in Jebel Irhoud, Morocco that also push back the multiple human origin theory (~300,000 years). In all likelihood from all these constantly emerging findings, Africa served as a massive nursery for humanity and no single genetic point was responsible for our existence.
Early humans probably transitioned from homo erectus to H.heidelbergenesis and then to the modern human we know today. The reason most anthropologists have been so stubborn about alternative theories was simply due to bad science. Absence of evidence is not evidence of absence and this fallacy occurs more often in science that we like to accept. Much like any other inquiry, anthropology has schools of thought and scientists compete with each other in order to support their hypothesis that very often found to be conflicting with new findings.
The "Multiregional" hypothesis once competed excessively with the "Out of Africa" hypothesis. The first was presumably disproven by DNA analysis showing that Homo Sapiens fossils around the world were more genetically similar than those from Africa — which suggests that they couldn't have evolved independently. Very few anthropologists though understood that the evidence only demonstrated how the earth was more likely populated rather than how it evolved. We had the data but the interpretation was completely false due to the fact the there were schools of thought that were already very well established with the "Out of Africa" hypothesis. In anthropology, the amount of evidence one needs to disprove something is exponentially greater than what is currently believed to be true. I believe this is also true for many other disciplines.
The DNA evidence of the boy from South Africa were solid enough to tell us that the boy was a member of San branch of the Khoe-San peoples of southern Africa, lived as a hunter-gatherer and spoke with the "click" language that identifies the people of the religion. Although fossils found on the beach are usually impossible for DNA recovering this guy provided us with such a solid sample that revealed a "genetic purity" aka had minimal procreative liaisons with members of other human groups compared to other specimens. From there on it is easy to use the DNA as a "molecular clock" to estimate possible mutations in retrospect to other specimens that had a common ancestor.
It is important to note here that "genetic purity" is something that brings ups lots of debates today in the academic environment due to the racial aspect and the political implications. This is also the reason why bad science creeps in scientific findings way too often and takes so much time to disprove the status quo. DNA is not perfect and neither are molecular clock mechanisms. They are subject to a large range of interpretation and they are still subject of debate. Nonetheless, the big picture here is that as more evidence comes along from palaeontological and archaeological sources the multiregional hypothesis only seems to gain ground.
