Out of Africa vs Multiregional Theory
Out of Africa vs. Multiregional Paleoanthropologists have been searching for decades, looking for signs of early human life throughout Africa Asia and Europe, trying to find clues that tell them where the human race originated. These scientists have found overwhelming evidence of early human life across different continents, but are always working to attempt to explain what they have discovered, and try to piece together the earliest signs of human civilization.
Two main theories have emerged related to the origin of our ancestors, the “Out of Africa Theory” and the “Multiregional Theory” (Ember, Ember, & Peregrine, 2009, p. 163). Both theories have merit, and evidence to back them up, causing controversial debate between Anthropologists. Each theory has its own support group and many varying theories surrounding them (Nei, 1991, p. 6720). The genetic backing of the “Out of Africa Theory” strongly supports the legitimacy of the theory, and provides evidence that it is a legitimate theory of how modern humans came to populate the earth.
To be more specific, the “Out of Africa Theory” deals with looking at DNA samples to link people from around the world to difference ancestors (Thorne & Wolpoff, 2003). This was seen in the movie, “The Human Family Tree”, by examining DNA through cheek swabs of various people who originated from across the globe, but were found in Queens, New York. Researchers found that overall our DNA is about 99% identical, regardless of where our more recent ancestors may have come from. This is due to a common female and male ancestor that scientists believe every person alive is related to.
These people are called Scientific Adam and Scientific Eve, and are both hypothetical humans who originated in Africa, and lived around 200,000 years ago and 100,000 years ago, respectively (Ember, Ember, & Peregrine, 2009, p. 163). Scientific Adam and Eve would be the genetic link for all currently living humans, such that mtDNA from Eve would be the same as mtDNA found in modern humans across the globe, passed on through the mother for generations. It also means that males pass on their Y chromosome, which can be linked to Scientific Adam, as recently as 100,000 years ago (Nei, 1991, p. 6721).
The movie discussed the long-term early human civilizations in East Africa, dating back to around 200,000 years, which is the source of all current human life (Geographic, 2009). These early humans would be the ones to travel slowly throughout the continents, populating larger and larger areas of the planet. Slowly but surely, these early humans made their way into Asia, Australia and Europe, leaving behind evidence of their migration as they went (Nei, 1991, p. 6720). Although it is hard to imagine a population moving hundreds of thousands of miles, The Human Family Tree, was able to offer some explanation.
The move did not simply happen all at one time, or even within generations. Anthropologists discussed the possibility of each group moving a small distance further than their direct ancestors, creating a slow move, often along coast lines, which unfortunately would leave little evidence on land (Geographic, 2009). The major support from this theory comes from genetic findings, which link the DNA of all modern humans, despite ethnic background and ancestral tracking (Nei, 1991, p. 6720).
This evidence shows that although humans come from many different countries, across various continents, we all share extremely similar DNA, and various minute changes in our genetic code can help link people to various tracks of early human migration (Geographic, 2009). Although evidence of other similar species were found throughout various continents, single-origin theorist believe that H. sapiens replaced them due to a type of biological or cultural advantage (Ember, Ember, & Peregrine, 2009, p. 163).
The movie, The Human Family Tree, also discusses that H. apiens may have been more able to handle environmental changes, than other species, leading to the extinction of one species, such as Neanderthals (Geographic, 2009). There is also debate as to whether or not H. sapiens may have interbred with Neandertahl populations, but no solid genetic evidence has been found to support the interaction (Nei, 1991, p. 6721). Although there is genetic evidence to support the single-origin theory, anthropologists who believe in the “Multiregional Theory” have argued that genetic evidence is flawed, and not strong enough to prove anything in regards to the single-origin theory.
Although this may have been true in earlier studies, current findings are significantly more reliable, and have found similar evidence (Ember, Ember, & Peregrine, 2009, p. 163). The “Multiregional Theory” is the idea that early hominids, such as H. erectus, and archaic H. sapiens had already populated the world, and independently evolved after already being established in different locations (Ember, Ember, & Peregrine, 2009, p. 163). This is a logical assumption, due to many anatomical similarities between many of the early hominid species to modern humans.
Many multiregional supporters also use the genetic evidence to their advantage by claiming it only proves that H. erectus is a common ancestor who migrated from Africa, which is a logical claim (Ember, Ember, & Peregrine, 2009, p. 164). It is hard to pinpoint what exact species the mtDNA or Y chromosome came from, if one were to argue that modern H. sapiens evolved from H. erectus at some point in our evolutionary history. However, if H. sapiens evolved from H. erectus after some time and migration, it still seems that it would be considered a single source of our genetics, which can be traced back to Africa.
Many multiregional theorists also argue that there is no sign of an invasion in any of the civilizations that have been found. However, this is counteracted by the idea that other species such as Neanderthals were simply not equipped for the environmental changes, and were killed off by natural selection (Thorne & Wolpoff, 2003, p. 50). On top of the single-origin and multiregional ideas, there are theories that allow for intermixing of various ideas from each theory, to create an intermediate theory.
It allows for wiggle room between the more strict ideas of the other theories, and accepts that there could have been replacement, interbreeding and natural causes that all caused the evolution to modern humans. This is supported by the study of body lice, of which there is only species, with two lineages, one found worldwide and one is strictly found in the Americas. This suggests that these lice were passed on from more archaic species to modern humans (Ember, Ember, & Peregrine, 2009, p. 165). In conclusion, the controversy that is found when researching the origins of modern humans is both necessary and reasonable.
Without controversial ideas, we would be unable to learn new things about our ancestry, and the thousands of years of evolution that have brought H. sapiens sapiens to their current place in time. Although there seems to be no specific answer, evidence for the “Out of Africa Theory” proves to be strong in scientific significance and logic, however, the idea of an intermediate theory brings about allowance of the merging of the two theories, to create a larger picture of the evolution of our species.
The research done throughout the movie The Human Family Tree has proven our incredible genetic similarities to all humans, regardless of our specific identified race, ethnicity or ancestry. The research provides fascinating insight into the true origin of modern humans, and will hopefully lead to further evidence as far as how we came to populate the entire earth, after starting in one location in Africa.