Ancestral Home Of Human Beings Discovered By Scientists
Researchers have now pinpointed a fertile river valley in northern Botswana as the ancestral home of human beings.
The earliest anatomically modern humans arose 200,000 years ago in a vast wetland south of the Zambezi river which was the cradle of all human beings, a new research study has revealed.
This fertile river valley- lush region – which also covered parts of Namibia and Zimbabwe – was home to an enormous lake that sustained our ancestors for 70,000 years, according to the study published in the journal Nature.
Between 110,000 & 130,000 years ago, the climate started to change & fertile corridors opened up out of this fertile valley. And now for the first time, the population began to disperse, paving the way for modern human beings to migrate out of Africa, and ultimately, worldwide.
Lead scientist Professor Vanessa Hayes who is a geneticist at the Garvan Institute of Medical Research in Australia said that it has been clear for some time that anatomically modern human beings appeared in Africa roughly about 200,000 years ago.
What has been long debated till now is the exact location of this emergence & subsequent dispersal of our earliest ancestors.
Professor Hayes and her team collected blood samples from study participants in Namibia & South Africa and they looked at their mitochondrial DNA. As mtDNA is passed almost exclusively from mother to child through the egg cell & its sequence remains the same over generations to generations, making mtDNA a useful tool for looking at maternal ancestry.
The research team focused their research on the L0 lineage that is the modern human’s earliest known population and compared the complete DNA code (mitogenome) from different individuals. Researchers also looked at other sub-lineages across various locations in Africa to see how closely were they related.
The team then combined genetics with geology & climatic physics, to paint a picture of what the world looked like about 200,000 years ago.
Geological evidence shows that the homeland region once housed Africa’s largest ever lake system- Lake Makgadikgadi-which was double the size of the modern Lake Victoria.
Climate computer model simulations indicated that the slow wobble of Earth’s axis” brought a periodic shift in rainfall” across this region.
Professor Axel Timmermann who is a climate scientist at Pusan National University in South Korea, said that these periodic shifts in climate would have opened green, vegetated corridors, first about 130,000 years ago to the northeast & then around 110,000 years ago to the southwest, allowing earliest ancestors to migrate away from their homeland for the first time.
Professor Hayes added that the team observed significant genetic divergence in the modern humans’ earliest maternal sub-lineages that indicates our ancestors migrated out of the homeland between 130,000 and 110,000 years ago.
The first migrants ventured northeast, followed by a second wave of migrants who traveled southwest. A 3rd population remained in the homeland until today.
Scientists believe that the humans who migrated southwest flourished and experienced steady population growth. Researchers say this could be due to an adaptation to marine foraging.
These first migrants left behind a homeland population said, Professor Hayes.
Eventually adapting to the drying lands, maternal descendants of the homeland population can be found in the greater Kalahari region today, he added.