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A controversial theory pretends to revolutionize the concept of human origins. In a new theory, a group of researchers claims that the first “fragmentation of the human species” occurred about two million years ago.
Scientists note: “Recent studies have established that genetic diversities are mostly maintained by selection, therefore rendering the present molecular model of human origins untenable. Using improved methods and public data, we have revisited human evolution and derived an age of 1.91-1.96 million years for the first split in modern human autosomes.”
Scientists from the Central-South University of Changsha, China, have proposed a theory that challenges the official version of the evolution of our species and that defines the human being as the heir of DNA transmitted by a small group of Homo sapiens which lived in Africa about 200,000 years ago.
In this group—known as mitochondrial Eve—experts believe, lived the first beings anatomically similar to modern day humans.
“Mitochondrial Eve: In 1987, a worldwide survey of human mitochondrial DNA (mtDNA) was published by Cann, Stoneking, and Wilson in Nature magazine. Its main point was that “all mitochondrial DNAs stem from one woman” and that she probably lived around 200,000 years ago in Africa.” (Source)
Instead of this theory, Chinese biologists defend the theory of multiregionalism, a second idea that was proposed in 1984 but has been discarded by most modern geneticists. This hypothesis asserts that the human being evolved from different ancestors that saw their origin in several regions of Africa, Europe, Asia and Australia in parallel, something that contradicts the evolutionary theory and genetic tests found so far.
The team of Chinese scientists has criticized the “molecular clock“ a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleotide sequences for DNA or amino acid sequences for proteins. The benchmarks for determining the mutation rate are often fossil or archaeological dates. The molecular clock was first tested in 1962 on the haemoglobin protein variants of various animals and is commonly used in molecular evolution to estimate times of speciation or radiation. It is sometimes called a gene clock or an evolutionary clock.
According to popular theories, the Homo sapiens migrated from Africa about 70,000 to 50,000 years ago and displaced extinct species such as Neanderthals and/or Denisovans, whose DNA structure is significantly different from that of the present human being.
Recent studies have established that genetic diversities are mostly maintained by selection, therefore rendering the present molecular model of human origins untenable. Using improved methods and public data, we have revisited human evolution and derived an age of 1.91-1.96 million years for the first split in modern human autosomes.
Experts note in their study: “We found evidence of modern Y and mtDNA originating in East Asia and dispersing via hybridization with archaic humans. Neanderthals and Denisovans were archaic Africans with Eurasian admixtures and ancestors of South Asia Negritos and Aboriginal Australians. Verifying our model, we found more ancestry of Southern Chinese from Hunan in Africans relative to other East Asian groups examined. These results suggest a multiregional evolution of autosomes and East Asia origin of Y and mtDNA, thereby leading to a coherent account of modern human origins.”
Their work has been pre-published in the bioRxiv scientific digital repository and proposes a new hypothesis: Maximum Genetic Diversity (MGD), which would explain the genetic variation in complex species as the human being and supports the idea of a multiregional evolution.
More importantly, this controversial research concludes that the first “fragmentation of the human species” occurred about two million years ago, something that completely revolutionizes the knowledge and current stands of the scientific community.
Featured image credit: SciencePicture Co/Corbis.