Scientists traced back to the original fertile land that sustained human beings for years. While some raise doubts on the new discovery others are excited by the new development.
If there are two eternal questions humans have always looked for answers to, it is where we come from and where we're headed. While there are endless possibilities to the latter, the answer to where we come from is something science can still provide answers to. Scientists have always tried to dissect the past of human civilization. They have come forward with new discoveries and theories that have only made us more curious with time. And while Africa is believed to be the cradle of all humankind, one recent discovery by a team of Australian scientists has narrowed it down to a rich wetland in Botswana.
A fertile valley in northern Botswana has been identified by scientists as the ancestral home of modern humans, according to The Independent. This vast wetland in the region severed as an oasis for the earliest anatomically modern humans known as Homo sapiens. The new study revealed that these humans originated 200,000 years ago in the vast wetlands found in the south of the Zambezi river.
“It has been clear for some time that anatomically modern humans appeared in Africa roughly 200,000 years ago. What has been long debated is the exact location of this emergence and subsequent dispersal of our earliest ancestors,” said lead researcher Professor Vanessa Hayes, a geneticist at the Garvan Institute of Medical Research in Australia.
According to the paper published in the journal Nature, the flourishing green land helped in the survival of human beings about 70,000 years ago. The region also covered parts of Namibia and Zimbabwe. However, a shift in the climatic conditions that opened up fertile grounds in other parts led to the spread of humans settlements outside Africa. “These shifts in climate would have opened green, vegetated corridors, first 130,000 years ago to the northeast, and then around 110,000 years ago to the southwest, allowing our earliest ancestors to migrate away from the homeland for the first time,” said Professor Hayes.
Researchers were able to make these major breakthrough discoveries after looking into the mitochondrial DNA from participants from Namibia and South Africa. The mtDNA that gets passed on from a mother to a child remains the same over generations. Scientists compared this DNA code from different people and looked at the L0 lineage and its sublineages across Africa to study if they were related. Genetics combined with the geology and climatic physics enabled them to figure out the world that existed decades ago.
"We 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 third population remained in the homeland until today,” said Hayes.
Based on the study, those that migrated to the southwest grew and flourished. They eventually adapted to different conditions. “Eventually adapting to the drying lands, maternal descendants of the homeland population can be found in the greater Kalahari region today.”
However, not everyone was convinced by the study. “How can they know that there aren’t old lineages in other regions if they’re not included in the study? It is not possible to make inferences about the geographical origin of modern humans in Africa based solely on patterns of variation in modern populations. This is because humans migrate over long distances. They migrated out of Africa and across the globe within the past 80,000 years and they have migrated across Africa in the recent and ancient past,” said Sarah Tishkoff, a geneticist at the University of Pennsylvania.
Though doubts still exist among few, the study is considered an important step in answering bigger questions.