The author discusses modern hypotheses of the course of human evolution, assuming that modern man, not a hominid, left Africa. However, how to explain the 'distant' Negroid genetics in such a model? All humans living outside Africa, are genetically closer to each other than Negroid populations are to each other. In other words, usually a Pole and a Japanese will be closer genetically than Negroes from different tribes within the same country. To explain such a large 'diversity' of Negro DNA, and especially their 'unique' because not found in any other populations DNA fragments, some scientists have hypothesized gene exchange with hominids. To mix with archaic hominids would be members of the population of the first humans, who did not leave Africa with the rest of the humans around 70-50k ya. According to this model, some fairly recent fossils (<20,000 years ago) have been found to be morphologically similar to archaic humans [32-35]. However, it is not clear what barriers (geographic, behavioral) allowed modern and archaic evolutionary lineages to remain distinct for hundreds of thousands of years before the recent mixing (this problem occurs only under the assumption that Homo sapiens came out of Africa, and not a hominid that evolved elsewhere, as was the case with Neanderthal). If the barriers were geographic, this model would predict that archaic morphology would persist quite late in some regions, as in Eurasia with Neanderthals, but only in Africa. Expectations for this model will also depend on whether there was sufficient gene flow and whether the genetic architecture of morphological traits was such that mixed individuals would differ morphologically from individuals that trace all their ancestry to that region. Ongoing studies [54] should provide a better understanding of how admixture affects morphology, which is key to distinguishing model 4 from model 1,3. Genetics There are no "archaic" ancient genomes comparable to Neanderthal and Denisovan sequences. Alternatively, several geneticists have taken the approach of looking for regions of the genome that are statistical outliers in modern African populations and may represent introgression between divergent human species [30]. For example, Hsieh et al. consider the top 1% of S* outliers in the genomes of Central African pygmies [55]; they find evidence of a single pulse of gene flow to Central Africans 9,000 years ago. These genetic regions tend to have a very old age of coalescence of about 1 million years. Rather than supporting evidence for extensive gene flow (i.e., Model 1), these data would tend to support a strong population structure for tens of thousands of years between hominin species - followed by one or two pulses of mixing with low rates of migration. However, caution should be exercised in interpreting such approaches, as any statistic will have a set of observations in the tail, the observed "introgressed" segments do not fit any of the simulated demographic models in the paper [55], and the authors emphasize that their approach is significantly subject to error in the estimated time of introgression.