DNA Consultants replaced its “beachcomber route” map of human migrations out of Africa with a “northern route” scheme more aligned with current phylogenetic and phylogeographic theory, said Donald N. Yates, principal investigator. “Although the exact timing and geographical details of the separation of the first Eurasians from Africans remain intensely debated, it is clear that a crossing over the Horn of Africa to Arabia and subsequent coastal route around India and Indonesia to Australia cannot explain the admixture with other hominids preserved in the oldest travelers along that road,” said Yates. “The northern route proposed five years ago by Rosa Fregel and Vicente Cabrera of the University of Laguna in Spain has overwhelming advantages and should be adopted as the new model.”
It was Stephen Oppenheimer’s The Real Eve that suggested as long ago as 2003 that the main out-of-Africa migration of humans proceeded across the mouth of the Gulf of Suez and around the coasts of Arabia, India and Southeast Asia—the “beachcomber” or southern route. Opposing Oppenheimer, an Oxford genetics professor, was an older theory of multiple dispersals through the Levant, championed by Cambridge University geneticists Marta Mirazon Lahr and Robert Foley.
In 2009, a massive project spearheaded by the Chinese seemed to put that question to rest. The 40-institution HUGO Pan-Asian SNP Consortium “strongly concludes the southern route made a more important contribution to East and Southeast Asian populations than the northern route,” said Li Jin, a population geneticist at Fudan University in Shanghai, China. Jin was one of the lead authors of a study reported in Science, vol. 326, no. 5959, p. 1470, “SNP Study Supports Southern Migration Route To Asia,” by Dennis Normile.
But the issue did not rest with SNPs. In 2010 began the era of ancient DNA. The bombshell arrived with the May 7, 2010 issue of Science Magazine. Entitled “A Draft Sequence of the Neandertal Genome,” it presented the years-long attempt of an international team of scientists to derive DNA from ancient female Neanderthal bones and determine if there was any genetic overlap with humans. There was, quite a lot. Later studies zeroed in on Denisovan, Neanderthal-Denisovan hybrid, Homo erectus, and “unknown hominid” admixture.
Our new map pays homage to the article, “Carriers of Mitochondrial DNA Macrohaplogroup N Lineages Reached Australia around 50,000 Years Ago following a Northern Asia Route,” published in PLoS One, June 8, 2015, by Rosa Fregel, Vicente Cabrera, Jose M. Larruga, Khaled K. Abu-Amero and Ana M. González (all at Spanish institutions).
According to the Spanish team, ancient DNA sequences embedded in modern samples showed that East Asians actually had more Neanderthal than Europeans, and Austronesians had significant Denisovan. Arabians and Indians had little of either. A northern dispersal route of some 5,000 years duration through territory with proven Neanderthal and Denisovan fossils made imminently more sense than the beachcomber route, which wasn’t supported by any fossils. Phylogenetics and phylogeography agreed.
“Combined genetic, archeological and bioclimatic evidence suggest that, although the early anatomically modern human was born in Africa, the nursery of the modern humans that colonized Eurasia, Oceania and the New World might be first at the south Siberia northwest China core and later in Southeast Asia,” the team concluded in 2015, more than five years ago.
“In the old model, the arrows mostly went east and then north, backtracking west,” said Yates. “In the new map our earliest ancestors are shown going north and then east and finally south, in a fundamentally opposite pattern.”
Lest anyone think that all problems are solved, there are still the matters of a possible Homo erectus contribution to humans’ family tree and the place of a recently discovered “mystery hominid in North Africa.” Debate between the continental and universal origins of humans continues. Also, the controversy has not abated over whether Macrohaplogroup L3 (the parent of the first haplogroups considered non-African) arose inside Africa or outside it, with or without Neanderthal input.