The Denisovan or Denisova hominin (pronunciation: /dᵻˈniːsəvə/ dɛ-NEE-sə-və) is an extinct species or subspecies of human in the genus Homo. Pending its status as either species or subspecies it currently carries the temporary names Homo sp. Altai, or Homo sapiens ssp. Denisova. In March 2010, scientists announced the discovery of a finger bone fragment of a juvenile female who lived about 41,000 years ago, found in the remote Denisova Cave in the Altai Mountains in Siberia, a cave that has also been inhabited by Neanderthals and modern humans. Two teeth belonging to different members of the same population have since been reported. In November 2015, a tooth fossil containing DNA was reported to have been found and studied.
Analysis of the mitochondrial DNA (mtDNA) of the finger bone showed it to be genetically distinct from the mtDNAs of Neanderthals and modern humans. Subsequent study of the nuclear genome from this specimen suggests that Denisovans shared a common origin with Neanderthals, that they ranged from Siberia to Southeast Asia, and that they lived among and interbred with the ancestors of some modern humans, with about 3% to 5% of the DNA of Melanesians and Aboriginal Australians deriving from Denisovans.
A comparison with the genome of a Neanderthal from the same cave revealed significant local interbreeding with local Neanderthal DNA representing 17% of the Denisovan genome, while evidence was also detected of interbreeding with an as yet unidentified ancient human lineage. Similar analysis of a toe bone discovered in 2011 is underway, while analysis of DNA from two teeth found in layers different from the finger bone revealed an unexpected degree of mtDNA divergence among Denisovans.
In 2013, mitochondrial DNA from a 400,000-year-old hominin femur bone from Spain, which had been seen as either Neanderthal or Homo heidelbergensis, was found to be closer to Denisovan mtDNA than to Neanderthal mtDNA.
“Advances in the sequencing and the analysis of the genomes of both modern and ancient peoples have facilitated a number of breakthroughs in our understanding of human evolutionary history. These include the discovery of interbreeding between anatomically modern humans and extinct hominins; the development of an increasingly detailed description of the complex dispersal of modern humans out of Africa and their population expansion worldwide; and the characterization of many of the genetic adaptions of humans to local environmental conditions. Our interpretation of the evolutionary history and adaptation of humans is being transformed by analyses of these new genomic data.”
Prehistoric Tales of Bubonic Plague.Carl Zimmer, NYT. Ken Croswell, Science Now.. But in a new study, published on Thursday in the journal Cell, researchers report that the bacterium was infecting people as long as 5,000 years ago.
"...Exactly what those early outbreaks were like is impossible to know. But the authors of the new study suggest that plague epidemics in the Bronze Age may have opened the doors to waves of migrants in regions decimated by disease.
“To my mind, this leaves little doubt that this has played a major role in those population replacements,” said Eske Willerslev, a co-author of the new study and the director of the Center for GeoGenetics at the University of Copenhagen.
"David M. Wagner, a microbial geneticist at Northern Arizona University who was not involved in the study, said that the new research should prompt other scientists to look at mysterious outbreaks in early history, such as the epidemic that devastated Athens during the Peloponnesian War. “It opens up whole new areas of research,” he said...."
CELL Published Study
The Willerslev Group, Center for Geogenetics at the University of Copenhagen
“…When hunter-gatherers in the Middle East began to settle down and cultivate crops about 10,500 years ago, they became the world’s first farmers. But two new papers suggest that they were at home on both the land and the sea: Studies of ancient and modern human DNA, including the first reported ancient DNA from early Middle Eastern farmers, indicate that agriculture spread to Europe via a coastal route, probably by farmers using boats to island hop across the Aegean and Mediterranean seas. “Archaeologists have long known that farming arose in the Middle East and then spread to Europe, because radiocarbon dating of hundreds of early sites shows a clear time gradient from east to west. But that is only a rough guide, and in recent years geneticists have been filling in the details of that picture by sequencing the DNA of both modern and ancient populations. While the relatively cool conditions at many European sites have helped preserve the DNA of ancient skeletons, researchers had not succeeded in sequencing DNA from the many skeletons found at very early Middle Eastern sites, due to their very hot and dry environments. That has left a big gap in their understanding of the very earliest steps in the spread of farming from the Middle East to Europe, which began at least 8000 years ago. “Since the early 1990s, a Spanish team has been excavating at three ancient farming sites in Syria, whose earliest dates range from 10,500 to 10,000 years ago—the very beginning of the agricultural revolution. Last week, in PLOS Genetics, the team reported having partially sequenced DNA from the mitochondria (the energy units of the living cell) of 15 skeletons from two of the sites, Tell Ramad and Tell Halula. This is the first report of ancient DNA from early Middle Eastern farmers.….”
Why did the apes split from the monkeys between the Oligocence (34-23 mya) and the Miocence (23-5 mya)? Michael Balter
“The team, which reports its discoveries online today in Nature, points out that the split between early apes and Old World monkeys took place during a time of dramatic environmental, climatic, and tectonic changes in East Africa. Indeed, the Oligocene-Miocene boundary was marked by numerous tumultuous geological events, including a collision between the land masses that make up Africa and Arabia on one side and Europe and other parts of Asia on the other. However, just why those changes led the two groups to split "is one of the mysteries we would like to solve" by further research, Stevens says, although she thinks that it could be related to changes in the kinds of food resources available to the primates.
Michael Steiper, an anthropological geneticist at Hunter College in New York City who has conducted numerous molecular studies of primate evolution, welcomes the new findings. "At long last they reconcile the fossil and molecular records of early apes and monkeys," he says.
And Fleagle, after whom one of the species was named, calls the discoveries "a wonderful story of perseverance" over many years of research. As for the team's claims to have found the earliest known ape and Old World monkey ancestors, he says that "their identifications are as good as they can be with the material in hand." The "real split" between the groups could have taken place even earlier, he says.
But Terry Harrison, an anthropologist at New York University in New York City, cautions that the team's claims could be wrong. "Despite the seductiveness of the conclusions, I'm skeptical about the interpretations," he says. Harrison thinks that Rukwapithecus, the claimed ape ancestor, could represent a primate that actually predates the ape-monkey split and that the dental features used to identify it as an ape are "questionable"; and he argues that Nsungwepithecus might not even be a primate, but rather a suiform artiodactyl, a piglike, hoofed animal. "Similar cases of mistaken identity have occurred in the past," Harrison says, including claims for Miocene primates in East Africa that turned out to be artiodactyls and other nonprimates.”
Researchers have long been frustrated by a paucity of fossils from this key period in evolution, which sits at the borderline between two major geological epochs: the Miocene (about 23 million to 5 million years ago) and the Oligocene (about 34 million to 23 million years ago). The earliest known fossils of early apes and Old World monkeys date from the early Miocene and have been found in just a handful of sites in Kenya, Uganda, and North Africa. Meanwhile, molecular studies of existing primates consistently suggest that these two groups arose during the Oligocene, leading scientists to wonder whether the molecular dates are wrong or if paleontologists have been looking in the wrong places.
Neanderthals have a reputation they do not deserve. Hunched over and hairy, these ancient hominins are often depicted as primitive and uncultured, resembling apes more than us.
But a mounting body of evidence suggests that, in reality, we share more similarities than differences. And one of the most famous features of Neanderthals is actually wrong.
After more than a century of alternative views, a new study has reconfirmed that Neanderthals once walked fully upright with a posture not unlike our own. They weren't hunched after all.
The reanalysis is based on an elderly male Neanderthal that was found in La Chapelle-aux-Saints, France in 1911. Creating a virtual reconstruction of the ancient skeleton's pelvis and spine, the authors say that both the stress on the hip and the position of the pelvis are not so different from modern humans.
When the research was extended to other Neanderthal skeletons, the vertebrae and pelvic bones also matched this model. Once thought to be a hallmark of modern humans, this suggests that the curve of your lower back is not so unique after all.
"On the whole, there is hardly any evidence that would point to Neanderthals having a fundamentally different anatomy," explains Martin Haeusler, a specialist in evolutionary medicine at the University of Zurich.
If Neanderthals really had a posture similar to humans, they would have needed a double s-shaped spine like our own. These curves exist to take on the majority of weight and shock that is conferred when walking.
But some recent studies using isolated vertebrae had argued that Neanderthals actually had straighter spines than we thought – backing up the idea that Neanderthals were hunched.
The new research, however, suggests this conclusion is a mistake.
After also looking at vertebrae in the neck, the researchers found evidence that Neanderthals had a double s-shaped curve similar to humans, with one curve in the neck and the other in the lower back.
As the evidence like this continues to grow, scientists are slowly coming to realise that there were less differences between the anatomy of humans and their ancient hominin cousins than we thought.
"Now is the time to recognise the basic similarities between Neanderthals and modern humans and to switch the focus to the subtle biological and behavioural changes that occurred in humans in the late Pleistocene," says Haeusler.
This study has been published in PNAS.