Study: The modern human race originated in Africa 300,000 years ago
A model designed to translate models from ancient anthropological literature into genetically testable demographic models - Nature.com
The oldest known human remains , discovered in Jebel Ijoud, located between Marrakech and the Atlantic coast of Morocco, showed that modern humans (Homo sapiens) originated in Africa more than 300,000 years ago.
However, the scarcity of human remains who lived in the early stages of history, and their dispersal in geographical areas far apart in Africa such as Ethiopia and South Africa, made it difficult to form a complete picture of how the human race originated and spread throughout the continent before moving to various parts of the world.
A new study, using genome data from modern African populations, offers a glimpse into how this might have happened.
The research indicated that several groups of human ancestors from across Africa contributed to the emergence of modern humans, as they migrated from one region to another, mixing with each other over hundreds of thousands of years.
The research concluded that all humans alive today can trace their roots back to two specific populations that lived in Africa about a million years ago.
The results did not support a long-standing hypothesis that modern humans appeared in a single region in Africa, nor did they support a scenario that assumed mixing with an unknown species closely related to humans within the continent.
The past is more complicated
"All humans share a relatively recent ancestry, but the issue in the distant past is more complex than our species evolving in one location alone or separately," said Aaron Ragsdale, a population geneticist at the University of Wisconsin-Madison.
Ragsdale is the lead author of the study published last week in the scientific journal Nature.
Ragsdale added: "It is likely that the ancestral groups spread over a (wide) geographical area and their population structure was 'weak', which means that there were permanent or at least frequent migrations between groups, which preserved the genetic similarity of our ancestors."
Scarce about our ancestors' remains, researchers have turned to collecting genome data from living people to find clues about the past.
They examined genetic data from 290 people, most of them from 4 geographically and genetically diverse African peoples, to track similarities and differences between groups and discover genetic connections over hundreds of thousands of years.
The subjects of the study included 85 people from the West African Mende group from Sierra Leone, 44 from the Nama Khoe-San group from the south of the continent, 46 from the Ethiopian Amhara and Oromo groups, and 23 from the Gumuz group from Ethiopia as well.
Genetic data from 91 Europeans was examined to determine the impact that occurred in the post-colonial era, and from Neanderthals, an extinct species of human that was concentrated in Europe until about 40,000 years ago.
The researchers said that the record of the remains is sparse in the time period that would carry more information about the emergence and spread of modern humans (Homo sapiens), and there is no ancient DNA from the remains of a skeleton or teeth from these time periods.
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