Studies of human DNA have found genetic changes or mutations over time that are distinct to certain groups of people. These distinctions are found in the mitochondrial DNA (mtDNA, passed down continuously only from mother to daughters) as well as Y chromosomes (which are passed down only from fathers down the male line).
Both Y chromosome and mtDNA types become genetic markers that enable human gene mapping of migrations and dispersal of human populations over time and place, through respectively male or female lines.
When these related genetic lines of human movement are plotted on a world map, they show the migration patterns through both male and female lines around the world. The distinct DNA markers are clear enough to show individual charting of male and female genetic movement of related peoples, going back 100,000 years to the earliest known human origins in eastern Africa.
What has been surprising in these mappings is, why are there differences between the movement of men’s and women’s genetic markers, sometimes quite disparately? (Fig.1)
The challenge to find the answer to this question was taken up by the Nusantara Academy of Development, Geocultures and Ethnolinguistics (NADGE), an independent research academy based in Malaysia and Indonesia. NADGE had in fact been doing its own studies of ethnic origins and population relationships among the Southeast-Asia/Pacific’s native Malayo-Polynesian peoples.
Observations during NADGE’s research show that there are at least two reasons why the migration charts of female genetic markers differ from that of males.
One reason, which in retrospect seems so obvious, is that male and female children of any given father and mother do not always migrate in the same direction.
NADGE Director and Lead Researcher A. Najib Ariffin explains, “A brother and a sister, each carrying the group’s paternal Y chromosome and maternal mtDNA respectively, may move in completely opposite directions and pass their genes along different routes.”
“So this male and female sibling separation rather than moving together,” Najib adds, “is one clear explanation of the dichotomy between men’s and women’s genetic marker distributions around the world.” He calls this the Male-Female Sibling Separation theory.
The other reason is less immediately obvious, but just as important and was discovered by Najib himself. It is basically that male and female mating partners may change within a lifetime of each man or woman.
Thus after having children with one mate, a man or woman may then have other children with another mate in another place, whose children will later migrate in directions other than that of the first half-siblings, whether male or female. This also contributes to the disparate migration routes between the genetic markers of the two genders. Najib names this the Polyparental Dispersion theory.
This observation began from Najib’s own family history, where both his native ethnic Malayo-Indonesian grandfathers had more than one wife each while his maternal grandmother was a member of the Qing imperial family of faraway China. This resulted in a widely spread family with a mix of several male and female genetic markers.
Najib even expands this mating partner observation, as follows, “In fact, the change of mating partners opens up at least two other lines of scientific enquiry; one in human genetic diversity, the other in social anthropology.”
“The first issue is, with the large number of possible DNA marker configurations between different male or female siblings of more than one shared father or mother, it is surprising that human genetic route differences are not even more convoluted than we can see on the human genome map.”
The other line of enquiry arising from this observation is the question of prehistoric human mating patterns and even marriage existence and its patterns then.
Najib explains, “In more recent human sociological history, we are used to the idea of the married father and mother family unit.”
“But thousands or more likely tens of thousands of years ago, we know little of how developed was this ‘pairing’ concept and practice in prehistoric society, and thus how it would have affected the differences in genetic movements of and between human population groups.” Najib is in fact interested to do more research into this aspect of human evolutionary history.
“All we do know,” Najib expounds, “is that there must have been persons who had children with more than just one partner, as people still do today, resulting in more genetic route diversity and cross-mixing.” He adds, “This multiple pairing could have been voluntary, or forced by separation through natural incidences such as death, disasters or even getting lost while searching for food, or forced as in abductions and taken to other places.”
Whatever it is, these explanations have helped to answer and even expand the matter of why there were baffling differences between the movements of male and female genetic markers in the great ancient human migration routes.
Najib’s research at NADGE on these issues is continuing and would be submitted to Malaysia’s National Science Academy as well as other scientific researchers for review.
Malaysian authorities are hopeful that more research such as these could one day lead to the nation’s first Nobel Prize nomination, especially in the Sciences.