The mysterious Denisovans were only formally identified about a decade ago, when a single finger bone unearthed from a cave in Siberia clued scientists in to the ancient existence of a kind of archaic hominin we’d never before seen.
But that’s only one side of the story. The truth is, modern humans had in fact already encountered Denisovans a long time before this. We crossed paths with them an eternity ago.
So far back, in fact, that we forgot about them entirely. Especially as they – and other archaic humans, such as the Neanderthals – faded into the unliving past, and Homo sapiens assumed sole human dominion over the world.
But even that’s kind of debatable.
All of these hominin varieties had a tendency to interbreed with one another when they co-existed, which is why, in a manner of speaking, ancient humans still live on in our modern human DNA.
Now, a new study reveals where the impression of this genetic fingerprint can most clearly be identified today.
According to the study, led by first author and human evolution geneticist Maximilian Larena from Uppsala University in Sweden, a Philippine Negrito ethnic group called the Ayta Magbukon has the highest level of Denisovan ancestry in the world today.
“Together with the recently described H. luzonensis, we suggest that there were multiple archaic species that inhabited the Philippines prior to the arrival of modern humans and that these archaic groups may have been genetically related,” the researchers explain in their study.
“Altogether, our findings unveil a complex intertwined history of modern and archaic humans in the Asia-Pacific region, where distinct Islander Denisovan populations differentially admixed with incoming Australasians across multiple locations and at various points in time.”
According to the results of the analysis – based on a comparison of around 2.3 million genotypes from 118 ethnic groups in the Philippines – the Ayta Magbukon’s level of Denisovan ancestry is approximately 30 to 40 percent greater than that of Papuans.
This is so, even though Philippine Negritos later ‘diluted’ their gene pool’s amount of Denisovan genetics, with a more recent admixture of East Asian bloodlines, which carry lower amounts of Denisovan bloodlines.
If that dilution effect is accounted for, the Ayta Magbukon’s level of Denisovan ancestry extends as high as 46 percent greater than Australians and Papuans, the researchers suggest.
Even without that manipulation, however, the evidence suggests the Ayta Magbukon mixed less with later arrivals than other Philippine Negrito groups: preserving traces of very old bloodlines from an archaic source – one destined, for a very long time, to be forgotten.
The research team worked with volunteers and indigenous cultural communities who participated in this study, and the project was recognized by and implemented in partnership with the National Commission for Culture and the Arts (NCCA) of the Philippines.
“Some groups, such as Ayta Magbukon, interbred only a little with the people who later migrated to the islands,” says population geneticist Mattias Jakobsson, also from Uppsala University.
“That’s the reason why the Ayta Magbukon retained most of their Denisovan genes and therefore have the highest levels of those genes in the world.”
The findings are reported in Current Biology.
SpaceX Crew Dragon cupola provides awe-inspiring view of the Earth from space – Californianewstimes.com
Give a few seconds (or a minute or two if needed) to startle and gaze at the Earth’s scenery from the recently launched SpaceX Crew Dragon above.
on Wednesday,Tied to the SpaceX Crew Dragon with one of the upgrades: Cupola. The transparent dome at the top of the Dragon Capsule provides the Inspiration 4 crew with the best views of the Earth that up-and-coming astronauts can dream of. This is the first time a cupola has been installed on a dragon. Dragons typically carry astronauts and cargo to the ISS, with docking ports at the top instead of windows.
A short video posted to the SpaceX Twitter account hours after the launch shows the cupola’s transparent dome against the Earth, which is a pale blue marble.
As the Crew Dragon orbits from a height of 585 kilometers (more than 360 miles), our planet is exposed to the sun and slowly roams around the orbs.
Inspiration 4’s crew (commander Jared Isaacman, doctor’s assistant, childhood cancer survivor Haley Arseno, aerospace engineer Chris Sembroski, African-American geology professor Sian Proctor) are in orbit for three days. Ride and stare at the cupola and the earth.
And did you say that the cupola is right next to the dragon’s toilet? Yeah, the view of the earth should be visible from the crew dragon’s bathroom. Isaacman told insiders Toilets are one of the few places where you can separate yourself from others with privacy curtains and have the best toilet windows of mankind. “When people inevitably have to use the bathroom, they will see one view of hell,” he said.
Astronauts who have been to space often talk about a phenomenon called the “overview effect.” Looking at the planet from above, the idea is that the way we think about the planet and the mass of humankind that depends on it will change. There may be a lot of revelation at the end of the Inspiration 4 journey, as I don’t know if they thought of it while sitting in the can.
The mission is the first mission to take off from the Florida coast on Wednesday night and be launched with four civilians. It is expected to return to Earth on Saturday and land in the Atlantic Ocean.
SpaceX Crew Dragon cupola provides awe-inspiring view of the Earth from space Source link SpaceX Crew Dragon cupola provides awe-inspiring view of the Earth from space
Oldest human footprints in North America found in New Mexico – Al Jazeera English
Fossilised footprints dating 23,000 years push back the known date the continent was colonised by thousands of years.
Footprints dating back 23,000 years have been discovered in the United States, suggesting humans settled North America long before the end of the last Ice Age, according to researchers.
The findings announced on Thursday push back the date at which the continent was colonised by its first inhabitants by thousands of years.
The footprints were left in mud on the banks of a long-since dried up lake, which is now part of a New Mexico desert.
Sediment filled the indentations and hardened into rock, protecting evidence of our ancient relatives, and giving scientists a detailed insight into their lives.
The first footprints were found in a dry lake bed in White Sands National Park in 2009. Scientists at the United States Geological Survey recently analysed seeds stuck in the footprints to determine their approximate age, ranging from 22,800 to 21,130 years ago.
“Many tracks appear to be those of teenagers and children; large adult footprints are less frequent,” write the authors of the study published in the American journal Science.
“One hypothesis for this is the division of labour, in which adults are involved in skilled tasks whereas ‘fetching and carrying’ are delegated to teenagers.
“Children accompany the teenagers, and collectively they leave a higher number of footprints.”
Researchers also found tracks left by mammoths, prehistoric wolves, and even giant sloths, which appear to have been approximately at the same time as the humans visited the lake.
The Americas were the last continent to be reached by humanity.
For decades, the most commonly accepted theory has been that settlers came to North America from eastern Siberia across a land bridge – the present-day Bering Strait.
From Alaska, they headed south to kinder climes.
Archaeological evidence, including spearheads used to kill mammoths, has long suggested a 13,500-year-old settlement associated with so-called Clovis culture – named after a town in New Mexico.
This was considered the continent’s first civilisation, and the forerunner of groups that became known as Native Americans.
However, the notion of Clovis culture has been challenged over the past 20 years, with new discoveries that have pushed back the age of the first settlements.
Generally, even this pushed-back estimate of the age of the first settlements had not been more than 16,000 years, after the end of the so-called “last glacial maximum” – the period when ice sheets were at their most widespread.
This episode, which lasted until about 20,000 years ago, is crucial because it is believed that with ice covering much of the northern parts of the continent, human migration from Asia into North America and beyond would have been very difficult.
Oldest human footprints in North America found in New Mexico – CTV News
Fossilized footprints discovered in New Mexico indicate that early humans were walking across North America around 23,000 years ago, researchers reported Thursday.
The first footprints were found in a dry lake bed in White Sands National Park in 2009. Scientists at the U.S. Geological Survey recently analyzed seeds stuck in the footprints to determine their approximate age, ranging from around 22,800 and 21,130 years ago.
The findings may shed light on a mystery that has long intrigued scientists: When did people first arrive in the Americas, after dispersing from Africa and Asia?
Most scientists believe ancient migration came by way of a now-submerged land bridge that connected Asia to Alaska. Based on various evidence — including stone tools, fossil bones and genetic analysis — other researchers have offered a range of possible dates for human arrival in the Americas, from 13,000 to 26,000 years ago or more.
The current study provides a more solid baseline for when humans definitely were in North America, although they could have arrived even earlier, the authors say. Fossil footprints are more indisputable and direct evidence than “cultural artifacts, modified bones, or other more conventional fossils,” they wrote in the journal Science, which published the study Thursday.
“What we present here is evidence of a firm time and location,” they said.
Based on the size of the footprints, researchers believe that at least some were made by children and teenagers who lived during the last ice age.
David Bustos, the park’s resource program manager, spotted the first footprints in ancient wetlands in 2009. He and others found more in the park over the years.
“We knew they were old, but we had no way to date the prints before we discovered some with (seeds) on top,” he said Thursday.
Made of fine silt and clay, the footprints are fragile, so the researchers had to work quickly to gather samples, Bustos said.
“The only way we can save them is to record them — to take a lot of photos and make 3D models,” he said.
Earlier excavations in White Sands National Park have uncovered fossilized tracks left by a saber-toothed cat, dire wolf, Columbian mammoth and other ice age animals.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
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