A story I read recently about a new species of hominid discovered in Siberia left me feeling struck with the power of science. Inside a cave in the Altai Mountains, a single bone was discovered – the tip of an animal’s little finger. From this, scientists extracted 30 milligrams of mitochondrial DNA. From that, they were able to determine that the creature is an evolutionary relative of modern humans and that, furthermore, it represents a fourth independent instance in which human ancestors radiated out from Africa:
The common ancestor is, however, too recent for the new species to be a remnant of the first human excursion from Africa, the one that led to Java man and Peking man, now known as Homo erectus. It is, in other words, a fourth example of anthropological tourism from Africa to the rest of the world, on what is now looking like a well-worn route. Yet it is the lone example. That shows how fragmentary and ill-understood human history is.
The finger bone was found in strata dated to between 48,000 and 30,000 years ago (the bone itself has not yet been dated). That means the creature was contemporary with both Neanderthals and modern humans in the area.
It seems to me that there has been no other area of human endeavour which could have revealed so much using so little. Certainly, it demonstrates how much information is contained in ancient genetic material, and how powerful its analysis can be for understanding the history of life on Earth.
This is absolutely mind-boggling. What I find really amazing is that science is slowly filling in the missing pieces of a puzzle, and one day, everything that we have learned may be proven wrong . We may also learn how it all started.
“That history turns out to be more intertwined than many had previously believed. Dr Paabo and his colleagues compared their Neanderthal genome (painstakingly reconstructed from three bone samples collected from a cave in Croatia) with that of five living humans from various parts of Africa and Eurasia. Previous genetic analysis, which examined DNA passed from mother to child in cellular structures called mitochondria, had suggested no interbreeding between Neanderthals and modern humans. The new, more extensive examination, which looks at DNA in the cell nucleus, shows this conclusion is wrong. By comparing the DNA of Africans (whose ancestors could not have crossbred with Neanderthals, since they did not overlap with them) and various Eurasians (whose ancestors could have crossbred with Neanderthals), Dr Paabo has shown that Eurasians are between 1% and 4% Neanderthal.”
The Denisovans are a mysterious branch of Homo. They were identified in 2010 by an analysis of the DNA of a bone discovered in a cave (occupied in the 18th century by a hermit called Denis) in the Altai Mountains in Russia. This bone was thought, when found, to be either Neanderthal or modern human, but the analysis showed it was neither. In the wake of that finding, a small percentage of Denisovan DNA has been discovered in various groups of people in Asia and the Pacific islands, Tibetans among them.
The human species is a lonely one. Today there are two species of gorilla, two of chimpanzees and a whopping three species of orang-utan, but just one sort of human. It wasn’t always so. People are familiar with the idea that Homo sapiens once shared Eurasia with another human, H. neanderthalensis. In 2004 researchers announced to great fanfare that they had found the bones of a third contemporaneous relative, a rather short human species who lived on the Indonesian island of Flores. This became H. floresiensis, and was quickly dubbed the “Hobbit”. Then, in 2010, geneticists declared that a single finger bone found in a cave in the Altai Mountains of western Siberia carried a distinct genome which suggested it belonged to a fourth group, the Denisovans.
The biggest surprise of Dr Paabo’s career, though, was probably the identification, purely from its dna, of an entire, new species, Homo denisova. The original genome of this species was extracted from a finger bone found in a cave in the Altai mountains of Russia. Denisovans were related more closely to Neanderthals than to Homo sapiens, and subsequent analysis has shown that the two sometimes interbred. More relevant from a present-day perspective is that both also interbred with Homo sapiens when that African species began turning up in their European and Asiatic homelands 70,000 years or so ago. The traces are still there, with modern Europeans having 1-2% of Neanderthal dna and some people in Asia and Australasia as much as 6% of Denisovan dna.
https://www.economist.com/science-and-technology/2022/10/05/this-years-nobel-science-laureates-have-now-been-announced