[Republic If You Can Keep It]

The assumption here seems to be that the origin of humankind was in Africa.

Is that the majority opinion now? Are there any knowledgeable dissenters?

Just curious.

[Right Wing Professor]

The assumption here seems to be that the origin of humankind was in Africa.

If I may...

There is no doubt we came out of Africa at some stage. There is some dissent about whether modern humans are entirely descended from humans that left Africa within the last 100,000 years, or whether there is some genetic contribution from the Neanderthal or Homo erectus populations that inhabited Eurasia previous to that, and may have been there for over a million years.

[expatpat]

I think it's accepted. Both the y chromosome track through males and a corresponding track through females lead to Africa. The Y chromosome method (where you track the mutations back into the past) leads to a (Bantu?) tribe who use clicks for communication.

Interestingly, these folks don't look like sub-Sahara faces (thick lips, dark skin) but have a variety of facial types, many looking like eskimos and central asians.

Apparently our aancestors migrated out of Africa, through the middle east, and stayed a while in central asia before spreading out to Europe, Siberia, and the Americas.

[Pharmboy]

Population Bottlenecks and Pleistocene Human Evolution
John Hawks,* Keith Hunley,† Sang-Hee Lee,‡ and Milford Wolpoff†
*Department of Anthropology, University of Utah; †Department of Anthropology, University of Michigan; and ‡Department
of Biosystems Science, Graduate University for Advanced Studies, Kanagawa, Japan
We review the anatomical and archaeological evidence for an early population bottleneck in humans and bracket
the time when it could have occurred. We outline the subsequent demographic changes that the archaeological
evidence of range expansions and contractions address, and we examine how inbreeding effective population size
provides an alternative view of past population size change. This addresses the question of other, more recent,
population size bottlenecks, and we review nonrecombining and recombining genetic systems that may reflect them.
We examine how these genetic data constrain the possibility of significant population size bottlenecks (i.e., of
sufficiently small size and/or long duration to minimize genetic variation in autosomal and haploid systems) at
several different critical times in human history. Different constraints appear in nonrecombining and recombining
systems, and among the autosomal loci most are incompatible with any Pleistocene population size expansions.
Microsatellite data seem to show Pleistocene population size expansions, but in aggregate they are difficult to
interpret because different microsatellite studies do not show the same expansion. The archaeological data are only
compatible with a few of these analyses, most prominently with data from Alu elements, and we use these facts to
question whether the view of the past from analysis of inbreeding effective population size is valid. Finally, we
examine the issue of whether inbreeding effective population size provides any reasonable measure of the actual
past size of the human species. We contend that if the evidence of a population size bottleneck early in the evolution
of our lineage is accepted, most genetic data either lack the resolution to address subsequent changes in the human
population or do not meet the assumptions required to do so validly. It is our conclusion that, at the moment,
genetic data cannot disprove a simple model of exponential population growth following a bottleneck 2 MYA at
the origin of our lineage and extending through the Pleistocene. Archaeological and paleontological data indicate
that this model is too oversimplified to be an accurate reflection of detailed population history, and therefore we
find that genetic data lack the resolution to validly reflect many details of Pleistocene human population change.
However, there is one detail that these data are sufficient to address. Both genetic and anthropological data are
incompatible with the hypothesis of a recent population size bottleneck. Such an event would be expected to leave
a significant mark across numerous genetic loci and observable anatomical traits, but while some subsets of data
are compatible with a recent population size bottleneck, there is no consistently expressed effect that can be found
across the range where it should appear, and this absence disproves the hypothesis.

[CobaltBlue]

Based on analysis of mitochondrial DNA, it is presently believed that the ancestors of all humans alive today are descended from people who were alive in Africa some 75,000 years ago.

That does not necessarily mean that human beings originated in Africa, only that our own ancestors did. Given that humans have existed for much longer than 75,000 years, a lot could have happened during the time before 75000 BC that we don't know about.