After Near Extinction, Humans Split Into Isolated Bands
After nearly going extinct 150,000 years ago, humankind split into small groups—living in isolation for nearly a hundred thousand years before “reuniting” and migrating out of Africa, a new gene study says. At one point our species may have been down to as few as 2,000 individuals, probably due to climate change—a longstanding theory bolstered by the new findings.
The research fills a gap in our understanding of what was happening in Africa before humans first left the continent.
“The assumption has always been that the original population [in sub-Saharan Africa] was very small but probably a single population,” said Spencer Wells, head of the Genographic Project, which oversaw the study.
“Turns out, that is not the case.”
(The National Geographic Society owns National Geographic News and funds the Genographic Project.)
The study appears in the current issue of the American Journal of Human Genetics.
Separate Ways
Around 200,000 years ago, modern humans emerged as a distinct species. All people alive today can trace their ancestry back to these humans, according to previous studies.
By the time the first great migrations out of Africa began, around 60,000 years ago, humanity had split into distinct populations with unique genetic lineages.
So what happened between 200,000 years ago and 60,000 years ago?
To find out, Wells and his colleagues analyzed 624 complete genomes of mitochondrial DNA—which is passed down from mothers—from various indigenous populations across sub-Saharan Africa. A genome is a person’s complete set of DNA (quick overview of human genetics).
DNA Tests Confirm IDs of Russian Tsar’s Children
DNA tests carried out by a U.S. laboratory prove that remains exhumed last year belong to two children of Tsar Nicholas II, putting to rest questions about what happened to Russia’s last royal family, a regional governor said Wednesday. The bone fragments dug up are those of Crown Prince Alexei and his sister, Maria, whose remains had been missing since the family was murdered in 1918 as Russia descended into civil war, said Eduard Rossel, governor of the Sverdlovsk region
“We have now found the entire family,” he told reporters in Yekaterinburg, the city where the remains were exhumed about 900 miles east of Moscow.
The confirmation could bring the tortured history of the Russian imperial family closer to closure and end royal supporters’ persistent hopes that members of the tsar’s immediate family survived the massacre.
Tsar’s Story
Nicholas II abdicated in 1917 as revolutionary fervor swept Russia, and he and his family were detained.
The tsar, his wife, Alexandra, and their son and four daughters were fatally shot on July 17, 1918, in a basement room of the merchant’s house where they were being held in Yekaterinburg.
The remains of Nicholas, Alexandra, and three of their daughters were unearthed in 1991 as the Soviet Union was collapsing.
Genetic tests convinced experts of their authenticity and identified one set as those of Anastasia, a daughter some have said survived.
The Russian Orthodox Church canonized Nicholas and his family in 2000, even as it expressed doubts that the remains were indeed those of the tsar’s family.
The remains of Alexei and Maria, however, had never been located, leading to decades of speculation that perhaps one or both had survived.