Posts Tagged ‘denisovans’
[URBAN NOTE] Five notes about smart animals: bees, wolves/dogs, cetaceans, Denisovans, Neanderthals
- The Conversation notes how urban beekeepers can play a key role in saving bees from extinction.
- Motherboard looks at the comparative intelligence, and generosity, of wolves versus their domesticated dog counterparts.
- National Geographic looks at how marine mammals, particularly cetaceans, have been used in different militaries.
- Smithsonian Magazine looks at how recent studies have demonstrated the diversity among Denisovan populations.
- Smithsonian Magazine looks at the new consensus about the remarkable capabilities of Neanderthals.
[NEWS] Five D-Brief links: whales, bacteria, offshore platforms, Falcon Heavy, Denisovans
- D-Brief notes the discovery of a fossil of a four-limbed whale in Peru, dating 42.5 million years.
- D-Brief looks at how the bacterium Enterococcus faecalis morphed from normal gut bacteria to potentially fatal hospital-borne infection.
- D-Brief notes a proposal to build offshore platforms as habitat for fish and for birds.
- D-Brief notes how the Falcon Heavy is proving itself a vanguard of progress in spaceflight.
- D-Brief notes new evidence of there having been multiple regional populations of Denisovans, drawing from work in Indonesia.
[LINK] “Skulls found in China were part modern human, part Neanderthal — and could be a new species”
The National Post carries Ben Guarino’s Washington Post article reporting on the exciting finds of mysterious hominid skulls in China. Could these actually be, as some speculate, remnants of the Denisovans, or of another still more obscure human population?
Modern humans outlasted the Neanderthals by about 40,000 years and counting. But don’t pat yourself on the back too firmly for outliving those troglodytes. Neanderthals crafted tools and tamed fire. They cared for their dead. Animal horns and blackened fire pits encircling the remains of a Neanderthal toddler suggest a 42,000-year-old funeral rite. If a Neanderthal indeed wore a talon necklace, as a collection of polished eagle claws indicate, they beat us to jewelry, too. Perhaps one of your ancient ancestors found the claw necklaces sexy: Some scientists theorize humans gave Neanderthals genital herpes and tapeworm parasites.
Their proportions, however, remained distinctly Neanderthal. Neanderthal bodies were shorter and stockier, more Gimli son of Gloin than Gigi Hadid. Their skulls were built differently, too, with a few features – like heavy brow ridges – particularly unlike ours.
Which makes a pair of newly-described skulls something of a wonder. The partial skulls have features up to this time unseen in the hominid fossil record, sharing both human and Neanderthal characteristics.
“It is a very exciting discovery,” as Katerina Harvati, an expert in Neanderthal evolution at the University of Tübingen in Germany who was not involved with the research, told The Washington Post. “Especially because the human fossil record from East Asia has been not only fragmentary but also difficult to date.”
Excavators dug up the skull cap fragments in 2007 and 2014, in Lingjing, located within China’s Henan province. The diggers discovered two partial skulls in a site thought to be inhabited 105,000 to 125,000 years ago, during an epoch called the Pleistocene. The owners of the skulls were good hunters, capable of fashioning stone blades from quartz. Ancient bones of horses and cattle, as well as extinct woolly rhinoceros and giant deer, were found strewn nearby the skull remains.
[LINK] “DNA from Neandertal relative may shake up human family tree”
I came across very recently Ann Gibbons’ September 2015 Sciencemag article noting yet another remarkable turn in the history of the hominid family.
In a remarkable technical feat, researchers have sequenced DNA from fossils in Spain that are about 300,000 to 400,000 years old and have found an ancestor—or close relative—of Neandertals. The nuclear DNA, which is the oldest ever sequenced from a member of the human family, may push back the date for the origins of the distinct ancestors of Neandertals and modern humans, according to a presentation here yesterday at the fifth annual meeting of the European Society for the study of human evolution.
Ever since researchers first discovered thousands of bones and teeth from 28 individuals in the mid-1990s from Sima de los Huesos (“pit of bones”), a cave in the Atapuerca Mountains of Spain, they had noted that the fossils looked a lot like primitive Neandertals. The Sima people, who lived before Neandertals, were thought to have emerged in Europe. Yet their teeth, jaws, and large nasal cavities were among the traits that closely resembled those of Neandertals, according to a team led by paleontologist Juan-Luis Arsuaga of the Complutense University of Madrid. As a result, his team classified the fossils as members of Homo heidelbergensis, a species that lived about 600,000 to 250,000 years ago in Europe, Africa, and Asia. Many researchers have thought H. heidelbergensis gave rise to Neandertals and perhaps also to our species, H. sapiens, in the past 400,000 years or so.
But in 2013, the Sima fossils’ identity suddenly became complicated when a study of the maternally inherited mitochondrial DNA (mtDNA) from one of the bones revealed that it did not resemble that of a Neandertal. Instead, it more closely matched the mtDNA of a Denisovan, an elusive type of extinct human discovered when its DNA was sequenced from a finger bone from Denisova Cave in Siberia. That finding was puzzling, prompting researchers to speculate that perhaps the Sima fossils had interbred with very early Denisovans or that the “Denisovan” mtDNA was the signature of an even more ancient hominin lineage, such as H. erectus. At the time, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who had obtained the mtDNA announced that they would try to sequence the nuclear DNA of the fossils to solve the mystery.
After 2 years of intense effort, paleogeneticist Matthias Meyer of the Max Planck Institute for Evolutionary Anthropology has finally sequenced enough nuclear DNA from fossils of a tooth and a leg bone from the pit to solve the mystery. The task was especially challenging because the ancient DNA was degraded to short fragments, made up of as few as 25 to 40 single nucleotides. (Nucleotides—also known as base pairs—are the building blocks of DNA.) Although he and his colleagues did not sequence the entire genomes of the fossils, Meyer reported at the meeting that they did get 1 million to 2 million base pairs of ancient nuclear DNA.
They scanned this DNA for unique markers found only in Neandertals or Denisovans or modern humans, and found that the two Sima fossils shared far more alleles—different nucleotides at the same address in the genome—with Neandertals than Denisovans or modern humans. “Indeed, the Sima de los Huesos specimens are early Neandertals or related to early Neandertals,” suggesting that the split of Denisovans and Neandertals should be moved back in time, Meyer reported at the meeting.
Researchers at the meeting were impressed by this new breakthrough in ancient DNA research. “This has been the next frontier with ancient DNA,” says evolutionary biologist Greger Larson of the University of Oxford in the United Kingdom.
