All people originated from ancestors in Africa.
No historical record exists that tracks the migratory patterns of the earliest humans. Scientists piece together the story of human migration by examining the tools, art and burial sites they left behind and by tracing genetic patterns.
It was a beautiful spot, a workshop with a glorious natural picture window, cooled by a sea breeze in summer, warmed by a small fire in winter.
Most scientists today agree that Homo sapiens — modern human beings –originated in Africa some 200,000 years ago, and that between 60,000 and 100,000 years ago, small groups began migrating out of Africa and spreading out across the continents.
Larger mtDNA than Y differences in matrilocal and patrilocal groups from Sumatra Gunnarsdóttir
Genetic differences between human populations are typically larger for YDNA than for mtDNA, which has been attributed to the ubiquity of patrilocality across human cultures. However, previous analyses of matrilocal groups give conflicting results… We find in the Semende significantly lower mtDNA diversity than in the Besemah as expected for matrilocal groups, but unexpectedly we find no difference in Y-chromosome diversity between the groups.
Humans are unique in having colonized so many types of environment. The environment can affect the dynamics of sexual selection, both in direction and in intensity, by altering either the sex ratio or the incidence of polygyny. This selective force probably varied from one human population to another but sexual selection has likely sculpted the human body in a multitude of ways difficult to demonstrate. A facial or body feature may result from an equilibrium among competing selective pressures, some sexual others natural. Sexual selection may use mental algorithms that have nothing to do with reproduction and several algorithms, both innate and (culturally) acquired, may be manipulated at one time. These algorithms are key to understanding how sexual selection works.
We can guess at the reasons why people migrated such as disputes between young males and alpha males, as seen in many primate troops, or the exclusion of lone members of a group, perhaps for anti-social behaviour, or to locate resources such as food and later on metals. My guess is that most early migrations were simply extended families that outgrew their niche and a subset set off to find a new niche probably not that far away.
Migration Maps depict where the Haplogroup Trees branch. Some Migration Maps give a generalised route for all migrations other maps show the Maternal and Paternal Lines separately; Maternal mtDNA and Paternal Y routes from Africa to Asia differ. Some Migration Maps show the chronology of migrations but not necessarily the world picture at the various chronological stages of migration. Some Macro Haplogroups remained for a long time in one area before a branch migrated away. The period around 50,000ya is notable for the widespread branching of Maternal and Paternal lines:
Y – BCT to CYAP to DE and Mt – LM to MN to NR and R to UB to F
People tend to migrate round obstacles and along pathways – by following a coastline or crossing the Steppes. Geographical boundaries of mountains and seas have meant that some groups have evolved in relative isolation. Migration Maps depict the regions where haplogroups branched but not necessarily where they are found in the pre-colonial era. Often the Macro Haplogroup becomes rare whilst an offshoot migrates and dominates a whole region e.g. Y-Hg F is rare but Y-Hg J is today prevalent in the Middle-East.
Depicting migrations in order of Haplogroup sequence and order of chronology shows the Paternal Y line in some regions arrived 10-20,000 years after the Maternal line and also suggests that early migrations are often replaced by later migrations.