this blogpost on the Eurogenes blog lays out more detail about the picture above. The above graphic was adopted from the one on the thread by one of the anthropology guys in the comments. The story behind the graphic is an interesting one for those of us who are fascinated by the events described in early Genesis.
Basically the blog moderator was describing how two "lobes" of Y-DNA (passed down from father to son) were highly successful and spread out over large areas starting just before or near the beginning of the Early Bronze Age. The northern lobe was the Y-haplogroup R1a. It spread into the regions in the red circle and the red arrows. It is associated with people who kept herds and were mobile. It completely dominated the area within the red circle and was a major component of the population in places shown by the red arrows.
According to most scientists today, this represents the last of the three major population groups which make up modern Europeans. The first group was the original inhabitants of Europe after the ice age, which were often Y-haplogroup I. Around eight or nine thousand years ago, the second group came from Anatolia (central Turkey) and introduced farming to Europe. They were Y-haplogroup G. Then came the Y-haplogroup R folks from eastern Europe and the Russian Steppe.
The other Y-haplogroup (black oval above) was not as dominant as R1a was over its territory, but it also expanded rapidly over a large area. This was Y-haplogroup J. The expansion area rich in this Y-haplogroup is shown above in black. These groups are known as agriculturalists, and civilization and monument builders. They were an advanced group.
The red area is an area of language dominance by Indo-European languages. The black area wound up not having a dominant language group even though there was genetic expansion. Part of the thread I linked to above had some anthropology guys wondering why genetic dominance was not matched by language dominance like in the red area.
The reason I mention all this is because it fits in so very well with what I see early Genesis is saying. This is very much the anthropological view laid out in "Early Genesis The Revealed Cosmology". Under this view of the text, Adam was not the progenitor of the entire human race. He was a type of Christ, not a type of God the Father. The reason why the text of early Genesis reads like there were other people around is because there were other people around.
The red northern lobe and the earlier expansion of the G-rich farmers from Anatolia into Europe was prompted by the "daughters of Adam" being taken as brides by chieftains of the surrounding tribes. They brought with them secrets of agriculture, domesticated livestock, and other aspects of civilization. Thus they spread rapidly. Some time later the Sons of Adam were destroyed by the flood of Noah's day. Despite how the text reads in most English translations, this was a regional flood aimed at purifying the line destined to produce the Redeemer, not a global flood which destroyed the entire human race. I know that is hard to see looking at the English translations, but the book goes into great detail showing what the original text is actually getting at.
When the descendants of Noah come out of the mountains, they find a Mesopotamia that is already somewhat civilized. They take it to greater heights until the dispersion described in Genesis chapters ten and eleven. The black oval on the picture above is actually saying the same thing that Genesis chapter ten is saying- its the table of nations graphically. It is the descendants of Noah becoming the dividers of the peoples into the nations of the near east. The early bible patriarchs were great men who picked up households of servants numbering in the hundreds. These would be the core of new nations as they spread. The spread of Y-haplogroup J at this time (Early Bronze Age) is what is described in Genesis chapter ten. The lack of "language dominance" from this group which puzzled the archaeologists on the above thread is touched on in the account of the tower of Babel. That account is also about a dominant ethnic group losing language dominance.