Twenty years ago, I realized all Northern European peoples are Ukrainian. When the ice age descended and glaciers covered most of Europe, a small section of Ukraine, now the disputed Crimea, was a place of refuge for Europeans. As the glaciers retreated, this remnant spread out over the whole continent. Later waves of migration brought genetics from other regions, but Scandinavia, the Netherlands and Scotland remain mostly descendants of people originating in what is now Ukraine. We know all this because of a unique Y chromosome. Unlike all other chromosomes, the Y does not undergo exchange of genetic material in meiosis. It remains pure and intact. And the Y chromosome which originated in Ukraine during the depths of the ice age is the same one most Northern Europeans have today. So we are all Ukrainian, in one small part at least.
But from whence came those people living in Ukraine in the ice age? If you believe many prominent paleontologists, all members of our species came from the same place: Ethiopia. I’m back in Ethiopia now in February 2023 and the wonderful and efficient Ethiopian Airlines used that theme on a commercial played before every one of its huge collection of great movies. I heard it so many times that I decided to check out the evidence.
I’d love it if all airlines were as efficient and friendly as Ethiopian is. And I’d love it if all peoples were are friendly and welcoming as the Ethiopians. But is this country the source of all humans? In one of their great museums here, they do have Lucy, a famous skeleton of any early hominid which some say is an ancestor of man. But no one contends Lucy is really human, even though she is more famous than most of us. She is even painted on many of the new cabs driving around Ethiopia’s capital, Addis Ababa..
To find the first humans, most scientists rely on DNA and try to trace back changes in the human genome as far as they can. Two types of DNA are most useful. The Y chromosome noted above and the mitochondrial genome. Both of these do not change through recombination in meiosis. So they have remained relatively intact and pure compared to the rest of the genome which gets mixed up every time a human produces sperm or eggs. All mitochondria we have come from our mothers. Our Y chromosome comes from our fathers.
If you trace the Y and mitochondrial DNA back, there is a most recent common male and female ancestor. So all humans have a common maternal ancestor of our mitochondrial DNA (“mitochondrial Eve”), as well as a common paternal ancestor for Y-chromosome DNA (“Y-chromosome Adam”). Its fascinating that the most recent research indicates both originated around 200,000 years ago in the lands inhabited by a tribe which still exists; some living much as they did back then.
Both were members of the group today known as the San–hunter-gatherers who once inhabited all of Southern and Eastern Africa. These folks were made famous in the 80s and 90s by the box-office hit movie series “The Gods Must Be Crazy.” The main character of the series was a hunter/gatherer tribesman, played by Nǃxau. The San are of short stature and have caramel skin–much lighter than most modern Africans–and the epicanthic eye folds of Oriental eyes. They speak in a “click” language, which uses as many different clicks as it does the sounds we use in English. Many of the San tribes boot out any members who marry non-San, so their genetics and culture have remained pure.
The San have always said they were the oldest people. Now science is catching up. Not only were they the source of the mitochondrial Eve and Y chromosome Adam, they were also the most populous group of humans on the planet for 150,000 years. Only about 1700 years ago did the much bigger and darker Bantu speaking farmers come from the North and take over the San territory. Many Southern and Eastern Africans today have significant San genetic heritage included South African President Nelson Mandela whose lighter skin and epicanthic eyes reflected DNA from the San.
The ancestors of today’s San people migrated North and East out of Africa into the Middle East and throughout the world. There they encountered Neanderthals and Denisovians and other species and interbred with them. After gradually changing appearance, language and culture while facing the challenges of settling the entire world, many came back to Africa.
Just as today’s Ukrainians have not the same genetics as the remnant which survived the ice age, today’s Ethiopians are genetically far removed from the original Homo sapiens. Today’s Ethiopia is dominated by peoples who arrived relatively recently from the Arabian peninsula. Perhaps including the reign of the Queen of Sheba, these people controlled both sides of the gulf of Aqaba including today’s Yemen, parts of Saudi Arabia and Djibouti and Eritrea and the highlands of present day Ethiopia.
In fact, the most common Y chromosome lineage in Africa didn’t start in Africa; it likely originated in the Middle East and was taken back to Africa by counter-migration.
So we have a common maternal ancestor of our mitochondrial DNA (“mitochondrial Eve”), as well as a common paternal ancestor for Y-chromosome DNA (“Y-chromosome Adam”). The diversity of our regular chromosomal DNA, however, shows us that these individuals were part of a large, genetically-diverse population and exchanged genes with many other populations including Neaderthals and Denisovians and likely others.
Today Europeans usually have about 2 percent of Neaderthal genes and some Asian peoples have up to 6% Denisovian DNA.
Most scientists hypothesize that Neaderthal and humans had a common ancestor long before the San and modern humans arose. Some of these left Africa and inhabited Europe and much of Asia for 500,000 years with little to no contact with the modern human/San. They developed distinct attributes including light skin and reddish hair as well as a larger brain than humans and a huge muscular body. Modern humans and Neaderthal did not cross paths until perhaps 50,000 years ago. Neanderthals went extinct in Europe around 40,000 years ago, roughly 10,000 years after first meeting Homo sapiens. This was enough time, however for plenty of mating between Neaderthals and modern humans. In modern humans, Neanderthal genes are associated with an increase in body size, lighter hair color and skin and a tendency to be a “morning person”.
While most research has assumed no Neanderthal genes in sub Saharan Africa, recent research indicates there is a small (0.01 per cent) portion of African DNA which is Neaderthal. The picture emerges is one of multiple migrations between Africa and Eurasia, with early humans making the intercontinental hop possibly several times over. When migration out of Africa hit its peak between 10,000 and 60,000 years ago, subsets of this group then trickled back into Africa in the last 20,000 years, mixing Neanderthal heritage into the continent’s human genomes. Today even one of the tribes called San which is open to out-marriage, now has some Neaderthal DNA.
So the Ethiopian Airlines slogan, “We are all Ethiopian”, is maybe a bit true, but we are all also Neaderthal and above all, San.
For some fun maps, go see these of European Y DNA d