Naturalis Historia: Volume VI

African Exodus

Scientists have long believed that humans originated in Africa. Ethiopia, to be exact, could be called our homeland. All the different types, shapes, and shades of people on Earth can trace their ancestry to African hunter-gathers 150,000 years ago. The evidence is in our DNA, right there in our bodies. Genetic mutations act as markers and can tell us our history. On the Y chromosome, all males share the same basic configuration, rooted in Africa. The marker M168 was carried out of Africa and is found on all non-African males. The diversity of genetic markers is greatest in Africa, which could only have arisen as DNA mutated over millenia. So you see, we are all African.

Part 1.
Time: 200,000 years ago
Where: Ethiopia
→ Most anthropologists and geneticists agree that modern humans arose about 200,000 years ago in Eastern Africa. The earliest modern human fossils were found in Omo Kibish, Ethiopia.

Part 2.
Time: 70,000-50,000 years ago
Where: Red Sea
→ A small group of modern humans left Africa for good (“Out of Africa II” model) between 70-50,000 years ago. All non-Africans are descendants of these travelers, who eventually replaced all earlier types of humans, including Neandertals. This exodus might have occurred around the top of the Red Sea or its narrow southern opening, bringing humans into the Middle East.

Part 3.
Time: 50,000 years ago
Where: Indonesia & Australia
→ Artifacts around 50,000 years old from two sites in Australia, Malakunanja and Lake Mungo, indicate that humans followed a coastal path along southern Asia and then island-hopped until reaching Australia. Their descendants, Australian Aborigines, remained genetically isolated on the island continent until the fairly recent colonization.

Part 4.
Time: 40,000-30,000 years ago
Where: Europe
→ It was assumed that humans migrated into Europe from North Africa. However, genetic data now shows that the DNA of today’s western Eurasians resembles that of people in India. In other words, Europe was populated by an inland migration from Asia only about 40,000 years ago.

Part 5.
Time: 40,000 years ago
Where: Asia
→ From the Middle East, humans pushed into Central Asia and arrived north of the Himalaya. Others traveled through Southeast Asia and China, eventually reaching Japan and Siberia.

Part 6.
Time: 20,000-15,000 years ago
Where: The Americas
→ Genetic evidence shows that humans in northern Asia eventually migrated into the Americas. 20,000 years ago, sea levels were low and land connected Siberia to mainland Alaska, allowing migration to occur. The travelers would have continued down the west coast into South America since ice sheets would have covered the interior of North America.

Source: Shreeve, James. “The Greatest Journey.” National Geographic Mar 2006: 61-69.
Related Article: Austro-Asiatic tribes of Northeast India provide hitherto missing genetic link between South and Southeast Asia.

Evolutionary Studies

Some articles on evolutionary studies:

Early Man Couldn’t Stomach Milk.
Chimps Use Spears To Hunt Mammals.
Chimp “Stone Age” Finds Are Earliest Nonhuman Ape Tools.

Animal-human hybrids

I was looking at this article from National Geographic. Animal-Human hybrids. Very interesting. I mean, genetic manipulations could be useful for cancer and disease patients, but some of this stuff seems unnecessary. What do you think?