The African origin of modern humans is the most widely accepted model in scientific (genetic) and paleoanthropological circles (Lahr and Foley 1994). The modern apes are not our ancestors. They share the same ancestor as human beings. That’s why they cannot evolve into human beings.
The hypothesis that humans had a single origin was noted by Darwin as far back as 1871.
Darwin described in his treatises: The Origin of Species and the Descent of Man that the Ape-like creatures at the head of human line of descent began to split 5 million years ago from those at the head of chimpanzees (chimps) line of descent.
The concept was speculative until recently – the 1980’s when it was corroborated by a study of present-day mitochondrial DNA (mtDNA) supported by anthropology of fossil findings.
Genetic and fossil evidence show that the archaic humans (hominids or Homo ergaster) evolved to anatomically modern humans solely in Africa, between 200,000 and 150,000 years ago. Subsequently they dispersed to Eurasia and other continents within the last 100,000 years (Stringer and Andrews 1988).
The date of the successful “Out of Africa” model of migration has been considered to be relatively recent, about 60,000 years ago. Once out of Africa, the Homo sapiens migrated into Eurasia and replaced all populations, which descended from Neanderthals in Europe and Homo erectus in Asia.
The routes followed by these African migrants remain poorly understood. The widely accepted route was from northeast Africa they crossed the Red Sea to Levant (present Israel, Jordan and Lebanon), and travelled until they reached India where they split into two groups: each going separate ways. This finds support in the archaeological and fossil records (Lahr and Foley 1994).
Takahata et al (1995), using 15 DNA sequence, estimated and confirmed that the divergence of humans and chimps from a common ancestor occurred 4.7 million years ago.
One group expanded along the coastlines of southern Asia until they reached the ‘foundered continent’ of Sahul (now Australia, New Guinea and Tasmania, all connected then as a land mass) some 46 thousand years ago. Another group travelled along the land route, northeast from India and later reached Europe.
A more recent view is that Austroasiatic speaking people such as Khasi in the northeast and Mundari in Chota-nagpur plateau (Jharkhand, Ranchi) were another wave of human migration from Africa to India and then to Indonesia and Australia (Nei and Ota 1991; Chu et al 1998; Sue et al 1999; Majumdar 2001).
The anthropological hypothesis is that these are prehistoric people, from the finding of skull and some fossil remains near Panchmare village in Gujarat, which were similar to the specimens found in northeast Africa (Kennedy 2000). The palaeoanthropological evidence
show that these Austroasiatic people inhabited India in the Palaeolithic period, about 60,000 years ago. This is supported by DNA markers.
Studies by Nicole Maca-Meyer et al (2001) concluded that “The first detectable expansion occurred around 59,000- 69,000 years ago from Africa, independently colonizing Western Asia and India, and following this southern route, swiftly reaching East Asia.
Khasi people (1 million) speak Khasi-Khymer – a subfamily of the Austroasiatic language, the others being Mundari, spoken by Munda tribal people of India and Nepal (17,000), and Mon-Khmer, spoken in Thailand, Cambodia, Vietnam and Laos (8 million).
The hypothesis that Homo sapiens including the Khasi people, originated in Africa, from which they expanded eastwards between 60,000 to 70,000 years ago, and 10,000 to 30,000 years later, the humans in western Asia spread to many areas including Europe and India, as well as back to northern parts of Africa, is based on genetic studies.
In genealogy, Y-chromosome and mitochondrial DNA (mtDNA) are the two most important parts of human genome in tracing our ancestral origin as they escape shuffling of genetic material between generations. Y is the one that makes a person male and it passes unchanged from father to son through generations.
Mitochondrial DNA also passes unchanged through generations. Vincent Cabera and colleagues from the University of La Laguna in Spain analysed the complete mitochondrial DNA sequence of 42 people in 2003.
Mitochondrial DNA is a very useful molecule for comparing different human populations because people inherit it entirely from their mother and the differences between mtDNA from different individuals accumulate over time as a result of mutations. Comparisons of mtDNA sequences from individuals representing different human lineages traced back 60,000 years.
Mitochondria live in the main body of the cell, outside the nucleus that holds the chromosomes. They generate chemical energy and heat. They are former bacteria that were enslaved a long time ago by animal cells.
According to American bacteriologist Lynn Margulis, Mitochondria were originally parasites, which attacked the larger bacteria, burrowing through the prey’s cell wall. Once safely inside they seal up the cell wall and eat the cell from within.
Over the generations, the mitochondrial ancestors evolved from the parasites that kill to less virulent parasites that kept their host alive to exploit it longer. Later still, the host cells began to benefit from the metabolic activities of the proto-mitochondria. Each came to benefit from each other.
When the sperm fuses with the egg all the sperm’s mitochondria are destroyed, leaving the fertilized egg containing only the mother’s mitochondria. All men in the world today carry the same Y chromosome, and both men and women carry the same maternal mitochondria.
The most ancient human mitochondrial lineages are L1, L2 and L3 specific for Africa. L3’s daughter lineages (northeast African) are M and N that left Africa to colonize temperate zones.
Lineage M is of particular interest in tracking the exodus of humans from Africa to India including Meghalaya and Manipur in the northeast. It can be used to infer information about the history of human migrations. The majority of people in Asia have been shown to carry mtDNA of a type known as haplogroup M, which has several subgroups.
Sue et al (2000) found that the Austro-Asiatic speaking tribals possess the highest frequencies of the ancient East Asian mtDNA HGM and exhibit the highest HVS1 nucleotide diversity, while high frequencies of Y-HGK are found among the Tibeto-Burman populations, mainly confined to northeast India and also among the Hans Chinese.
Their findings (Su et al 2000) indicate that the Tibeto-Burman speakers entered India from the northeastern corridor. The Dravidian tribals were possibly widespread throughout India before the arrival of the Indo-European speaking people, but retreated to southern India to avoid dominance.
Based on a study of Y- chromosomal haplotypes, Su et al (2002) have contended that after the proto-Tibetanburman people left their homeland in the Yellow River, the Baric branch moved southward and peopled the northeastern Indian region after crossing the Himalayas.
Analabha Basu et al (Ethnic India – a genomic view, 2003, Kolkata) studied the Austroasiatic speaking tribals, the Tibetoburman speaking tribals (Meitei excluded) and Dravidian speaking tribals of India. In their opinion, the Austroasiatic speaking tribals may be the earliest inhabitants of India whereas Tibetoburman speaking tribals are later immigrants from Tibet and Myanmar. The two groups can be differentiated on the basis of Y- chromosomal haplotypes.
A study by Sunghamitra et al (A prehistory of Indian Y- chromosome, 2005, Kolkata) found that the dyadic Y- chromosome composition of Tibetoburman speakers of India can be attributed to a recent demographic process, which appears to have absorbed and overlain populations who previously spoke Austroasiatic languages.
A recent study (2007) by Indian scientists, Kumar et al from Hyderabad in collaboration with the Department of Anthropology, North Eastern Hill University at Shillong, studied the Y- chromosome of the Khasi population and found evidence suggesting a common paternal heritage of Austroasiatic populations of India with those of the Southeast Asia.
Another study (2007) by Reddy et al from Hyderabad again in collaboration with the North East University at Shillong and Genome Institute of Singapore studied mtDNA and Y- chromosomes, SNP and STR data of the eight groups of the Austroasiatic from Northeast India and compared with those of other relevant Asian populations.
Their findings suggest that the Austroasiatic Khasi tribes represent a genetic continuity between the populations of South and Southeast Asia, thereby advocating that Northeast India could have been a major corridor for the movement of populations from India to East/Southeast Asia.
They found a distinct origin of the Khasi tribe in the predominantly though ethnically dissimilar Tibetoburman populations of Northeast India (Meitei excluded). The Khasi have Indian specific mtDNA.
The above views are consistent with my hypothesis that Austroasiatic speaking Khasi and non-Tibeto-Burman speaking Meitei are ethnically different from the Tibeto-Burman speaking tribals in Northeast India.
While Khasi language is definitely proven to be Austroasiatic, the Meitei language remains unclassified (previously ‘lumped’ erroneously as a Tibetoburman).
The Meitei language (spoken by 1.4 million) has some lexical cognates with the Kuki-Chin group (50 or so), but it does not serve as evidence for a special relationship as a Tibeto-Burman language. It only shows their absolute relationship (Matisoff & Van Driem 2001).
Van Driem has proposed the geographical name of Trans-Himalayan rather than Tibeto-Burman in 2004.
Cross-reference: This article is an excerpt from my Book – “The origin of the Meitei of Manipur & Meiteilon is not a Tibeto-Burman language” [2009, Dr I Mohendra Singh, B Sc,
MBBS, MD, MRCGP (London)] ISBN -81-220-0713-9
The writer is based in the UK
Van Driem (55), and an authority on Tibeto-Burman languages in collaboration with geneticists have led to advances in the reconstruction of Asian ethnolinguistic prehistory. His theory is that Hmong-Mien and Austroasiatics are the first domesticators of Asian rice and published a theory on the homelands and prehistoric dispersal. He has replaced the unsupported Sino-Tibetan hypothesis with Tibeto-Burman phylogenetic model, for.