If one is to believe that we are the product of a God, one made in his own image, then one simply needs to ask which God or, moreover, which "image" given that there were at least two, possibly more, such images of mankind before we finally made an appearance about 200,000 years ago. We can also be certain that our European lineage began in Ethiopia, as well as Kenya, East Africa.
There will be many who would love to totally disregard the facts relating to the evolution of man. Nonetheless, the facts speak for themselves.
Recent anthropological discoveries, however, have shed light on yet an earlier example of man, possibly an early Mark 1 version, called the Denisovans. Mitochondrial DNA analysis, at various levels, has shown that there could yet be possibly up to two more species of man waiting to be discovered that would make up our own DNA if all interbred with one another. It was more a case of being with "the one you're with" when it came to breeding, rather than looks.
The spread of humans and their large and increasing population has had a profound impact on large areas of the environment and millions of native species worldwide. Advantages that explain this evolutionary success include a relatively larger brain with a particularly well-developed neocortex, prefrontal cortex and temporal lobes, which enable high levels of abstract-reasoning, language, problem solving, sociality, and culture through social learning. Humans use tools to a much higher degree than any other animal, are the only extant species known to build fires and cook their food, as well as the only extant species to clothe themselves and create and use numerous other technologies and arts.
Humans are uniquely adept at utilizing systems of symbolic communication such as language and art for self-expression, the exchange of ideas, and organization. Humans create complex social structures composed of many cooperating and competing groups, from families and kinship networks to states. Social interactions between humans have established an extremely wide variety of values, social norms, and rituals, which together form the basis of human society. The human desire to understand and influence their environment, and explain and manipulate phenomena, has been the foundation for the development of science, philosophy, mythology, and religion.
Humans began to practice sedentary agriculture about 12,000 years ago, domesticating plants and animals, thus allowing for the growth of civilization. Humans subsequently established various forms of government, religion, and culture around the world, unifying people within a region that, over a period of thousands of years, led to the development of states and empires.
The Denisovans lived at a time when our ancestors, and the Neanderthals, were fishing and hunting, wearing jewelry, painting caves and making animal carvings.
The DNA test show that the tooth and finger bone of a young female discovered in a cave in Siberia came from different set of people. The study found extracts of Denisovan DNA in modern day inhabitants of Melanesia - the islands to the north and east of Australia which include New Guinea. That suggests the Denisovans interbred with the ancestors of Melanesian and may have been widespread in Asia.
The new species appears to have been a 'sister group' to the Neanderthals and its discovery paints a complicated picture of human evolution and migration out of Africa - the cradle of mankind. It is recognized that one group of early human ancestors left Africa between 300,000 and 400,000 years ago and quickly split up.
One branch evolved into the Neanderthals and spread through Europe, while the other moved east and became Denisovans. Again, Neanderthal and Denisovan’s are believed to have bred with anatomically modern humans, thus contributing to the genetic diversity of many people today. That being said, this new discovery suggests that our genetic diversity is far more complex, and again, includes a being (or beings) that has yet to be identified.
Anatoly Derevianko, leader of the Altay excavations and director of the Institute of Archaeology and Ethnography in Novosibirsk, thought the bone might belong to a member of our own species, Homo sapiens. Sophisticated artifacts that could only be the work of modern humans, including a beautiful bracelet of polished green stone, had previously been found in the same deposits. But DNA from a fossil found earlier in a nearby cave had proved to be Neanderthal, so it was possible this bone was Neanderthal as well.
Derevianko decided to cut the bone in two. He sent one half to a genetics laboratory in California; so far he has not heard from that half again. He slipped the other half into an envelope and had it hand-delivered to Svante Pääbo, an evolutionary geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. It was there that the case of the Denisovan pinkie bone took a startling turn.
Pääbo, a transplanted Swede, is arguably the world’s leading expert in ancient DNA, especially human DNA. His milestones are many. In 1984 he became the first person to isolate DNA from an Egyptian mummy. In 1997 he accomplished the same feat for the first time with a Neanderthal, a kind of human that vanished more than 25,000 years before the Egyptian pharaohs.
Whoever the mystery people were, they are a reminder that inbreeding was rife in human evolution. After our direct ancestors expanded out of Africa, they interbred with both Neanderthals and Denisovans. Although the ancestors of modern African hunter-gatherers never left the continent, recent studies suggest they did breed with an unidentified hominid species. That episode appears to have happened around 35,000 years ago, with a species that had split from our lineage 700,000 years ago
"The best explanation is that the Denisovans interbred with a yet unidentified species, and picked up some of their DNA. Denisovans harbor ancestry from an unknown archaic population, unrelated to Neanderthals. What it begins to suggest is that we’re looking at a Lord of the Rings type world – one where there were many hominid populations.” Mark Thomas, evolutionary geneticist at University College London.
Published in Nature, the research presented the ancient genomes of ancient humans that had been revealed at a meeting at the Royal Society in London.
Researchers said that much more interbreeding went on between different species of humans than had been believed. Among the participants was an ancestor of humankind from Asia about which nothing is known. they were also able to theorize that inter-species sex took place 30,000 years ago.
Mark Thomas, an evolutionary geneticist at University College London, said: "What it begins to suggest is that we're looking at a Lord of the Rings-type world - that there were many hominid populations."
Recent research by scientists at the University of Adelaide in Australia and the Natural History Museum in the UK found that Denisovans bred with modern humans around 50,000 years ago."Intriguingly, the genetic data suggest that male Denisovans interbred with modern human females, indicating the potential nature of the interactions as small numbers of modern humans first crossed Wallace's Line and entered Denisovan territory," the study authors said. Researchers at the Royal Society meeting said the interbreeding contributed to the genetic diversity of humans today.
Humans whose ancestors came from outside Africa are around 2% Neanderthal, while some people from Oceania are 4% Denisovan.
David Reich, an evolutionary geneticist at Harvard Medical School in Boston, said Denisovans interbred with an extinct population of archaic humans that lived in Asia, raising questions about this new species.
However, he also noted that the conclusions about interbreeding were based on low-quality genome sequences which he said were flawed.
Chris Stringer, of London's Natural History Museum, said: "We don't have the faintest idea [about the identity of the new species]."