Although scientists agree the human species began in Africa, it’s still not exactly clear how they managed to leave the continent and populate the rest of the world. Researchers may have finally solved this ancient mystery after finding sufficient evidence to suggest that the very first humans to leave the African continent did so out of what is now Egypt.   

Evolution is still a mysterious subject and the only clues that scientists have had to better understand the past are fossils. However, recent advancements in genetics have given scientists a new tool to help them decode the story of human life on earth: the genome. In a recent study, scientists scoured an extensive public catalogue of the genetic diversity in the Ethiopian and Egyptian populations looking for clues to humans’ earliest emergence from Africa.

As reported in the press release, the team produced whole-genome sequences for 225 people from modern Egypt and Ethiopia and found that the DNA of the Egyptian samples were more similar to non-African samples and present in higher frequencies outside Africa than the Ethiopian samples. This would suggest that Egypt was the most likely route for the very first human exodus from Africa into the rest of the world.

"It is exciting that, in our genomic era, the DNA of living people allows us to explore and understand events as ancient as 60,000 years ago," Dr. Luca Pagani, first author of the study, explained in the press release.

Along with identifying the exit route, the team was also able to estimate around what time the group of ancient humans first left, placing the exodus date at around 55,000 years ago — a whole 10,000 years earlier than previously believed.

The human exodus out of Africa is arguably one of the most poignant marks in our species' history. It allowed humans to spread throughout the planet adapting new traits, such as fairer skin to better get vitamin D in environments without much sunlight. The exodus also changed the human DNA, forever adding a bit of Neanderthal genes to the human genome as a result of our ancient ancestors mixing with their northern hominid cousins.

Fossil records show the Neanderthals left Africa and populated what is now Europe and Asia several hundred thousand years before ancient humans. According to National Geographic, when our ancient ancestors finally left Africa, following in the footsteps of the Neanderthals, interbreeding between the two species was so common that today nearly every human, except for indigenous sub-Saharan Africans, have a tiny bit of Neanderthal DNA preserved in their genes as living evidence of this great migration. Indigenous sub-Saharan Africans have no Neanderthal DNA because their ancient ancestors never made this journey.

The recent discovery of a northern route out of Africa is fascinating, but there are still many questions about the beginning of the human race that remain unanswered. For example, the team plans to conduct further genetic testing to find out if a second smaller exodus out of Africa also occurred via a southern route.

“To answer this, we need ancient genomes from populations along the possible routes. Similarly, by adding present-day genomes from Oceania, we can discover whether or not there was a separate, perhaps southern, migration to these regions,” Dr. Chris Tyler-Smith, a senior author on the study, explained in the press release.

Source: Pagani L, Schiffels S, Gurdasani D, et al. Tracing the Route of Modern Humans out of Africa by Using 225 Human Genome Sequences from Ethiopians and Egyptians. AJHG. 2015.