An evolutionary biologist has challenged the long-held theory that suggests the first humans emerged from African.
Dr Huan Shi, from China, proposed evolution began in East Asia where fossils predating the Africa timeline have been found.
Evidence of genetic diversity is at the heart of his ‘out of East Asia’ theory, based on a concept called ‘maximum genetic diversity’ (MGD) that states complex species are more likely to have less genetic diversity.
Dr Huang said that because East Asian populations have the least genetic diversity, they are likely to be the true ancestors.
Ancient Europeans were also found to be much closer to East Asians, he argued, both in terms of their paternal and maternal genetic makeup.
By this logic, the archeological finds of early humans with the most genetic similarities both to each other and to the wider, far-flung human race of today are the most likely candidates for the origin of the species, Dr Huang has contended.
If the ‘out of Africa’ model were correct, the now recently retired biologist noted that the DNA from 45,000-year-old European specimens would more comprehensively match ancient African DNA.
‘Ancient DNA [aDNA] from the oldest modern humans found in Europe, which was published this week,’ Dr Huang said late this December, ‘again showed closer similarity to Asians rather than Africans.’
‘Out of Africa,’ he boasted, ‘has been repeatedly disproven by aDNA!’
Dr Huang Shi’s ‘out of East Asia’ theory – supported by analyses of ancient DNA – proposes that humans first emerged in Asia where fossils predating the Africa timeline have also called the established theory into question. Above: a map of sites with the oldest human remains
A 2017 analysis finds the Dali skull (pictured) shares many characteristics with modern humans – a find that supports Dr Huang’s ‘out of East Asia’ hypothesis
The reason that his MGD theory holds, he said, is that more complex organisms like humans require many more parts of their DNA work together in concert, meaning that there’s less room for mutations acting like genetic ‘improvisations’ to survive.
‘A simple thought experiment can explain,’ Dr Huang wrote in an article published this past November in the Chinese-language journal Prehistoric Archaeology.
‘You can create three different groups of organisms — yeast, fish and humans — using the same gene sequence, and then let these three organisms diverge for a long time or about 500 million years.
‘A gene in yeast will change a lot, such as 50 percent, and its corresponding gene in fish will also change more but less than yeast, such as 30 percent,’ he continued, ‘[but] its corresponding gene in humans will change very little, such as 1 percent.’
This documented trend in the history of various species suggests that dramatic mutations in more complex creatures are less likely to survive evolution’s long haul.
Dr Huang, who was a professor of epigenetics at Central South University’s Center for Medical Genetics in Hunan before retiring, has had trouble getting mainstream academia to accept his theory. But scholars dismiss it less and less.
‘The MGD hypothesis is an innovative yet indeed controversial theory,’ said the Stanford-trained anthropology researcher German Dziebel.
Dziebel pointed out that there is broad consensus that older European human DNA samples are less diverse than the more recent samples.
MGD theory and thus the ‘out of East Asia’ theory that it supports ‘has potential,’ according to Dziebel, ‘and needs to be developed further.’
Above, a dramatized portrait of a primeval caveman wearing animal skin and hunting with a stone-tipped spear
‘Ancient DNA from the oldest modern humans found in Europe,’ Dr Huang said this month, ‘showed closer similarity to Asians rather than Africans.’ Above, a map of genetic differences showing how close ancient Europeans and Asia DNA has proven to be (bottom region)
Evidence that has emerged from other academic disciplines, including linguistics and kinship anthropology, has tended to bolster the theory too, Dr Huang said.
That has included analysis of the remarkably complete ‘Dali skull’, uncovered in 1978 in the China’s Dali County in Shaanxi Province.
This 260,000-year-old skull, unearthed with its face and brain case still in tact, was scrutinized by experts from Texas A&M University and the Chinese Academy of Sciences in 2017, who found it shares many characteristics with modern humans.
The ‘Dali skull’ was found to be notably similar to what had once been the earliest known fossil of Homo sapiens, found 6,200 miles away in Morocco.
Rather than pick a side in the ‘out of Africa’ vs ‘out of East Asia’ debate, these researchers tried to pick a compromise route.
Homo erectus (skull pictured left, reconstruction pictured right) is thought to have been a key early human ancestor in our own evolution. The Chinese ‘Dali’ skull was originally thought to be from Homo erectus, but the 2017 analysis shows it is remarkably similar to Homo sapiens
‘I think gene flow could have been multidirectional, so some of the traits seen in Europe or Africa could have originated in Asia,’ Texas A&M Professor Sheela told New Scientist.
But, for context, the dominant ‘out of Africa’ hypothesis on human origin has long maintained that modern humans first appeared in southern Africa only around 50,000 years ago — hundreds of years after the ‘Dali’ Homo sapien lived and died.
‘The out-of-Africa advocates are basically silent at the moment because they have made almost no progress in the last 10 years,’ Dr Huang told the South China Morning Post.
Scientists have also found the skull of an ancient human in China – homo julurensis – that would have had the biggest brain of any known hominin based on the abnormal size of its skull (above as digital renders). This smart ancient human may also bolster Dr Huang’s theory
By comparing skull fragments found in China (above), experts estimate that homo julurensis would have had a skull volume of 1700 ml – much larger than any other known hominin
This growing body of corroborating evidence has been a cause for optimism for Dr Huang and his fellow proponents of the East Asia theory.
In the eight years since Dr Huang and his team first presented their ‘out of East Asia’ theory at an international academic conference in 2016, he has been unable to find an academic journal outside of China that is willing to publish the theory.
‘We tried to submit the paper to many journals and were rejected, so we gave up,’ Huang said.
‘Any intellectual who wants to overturn popular opinion will experience the same difficulties,’ he opined. ‘But it’s fine as long as what you’re promoting is true and you don’t care how long it takes [to be accepted].’
