Connect with us

Science

Ancient DNA analysis yields unexpected insights about peoples of Central, South America

The Azeri Times

Published

on

Ancient DNA analysis yields unexpected insights about peoples of Central, South America
November 8, 2018, Harvard Medical School

The exterior of the rock shelter site of Lapa do Santo in Brazil. Credit: André Strauss

An international team of researchers has revealed unexpected details about the peopling of Central and South America by studying the first high-quality ancient DNA data from those regions.

The findings include two previously unknown genetic exchanges between North and South America, one of which represents a continent-wide population turnover.

The results suggest that the people who spread the Clovis culture, the first widespread archaeological culture of North America, had a major demographic impact further south than previously appreciated.

The authors analyzed genome-wide data from 49 individuals from Central and South America, some as old as 11,000 years. Previously, the only genomes that had been reported from this region and that provided sufficient quality data to analyze were less than 1,000 years old.

By comparing ancient and modern genomes from the Americas and other parts of the globe, the researchers were able to obtain qualitatively new insights into the early history of Central and South America.

Published in the journal Cell, the study was led by researchers at Harvard Medical School; the Howard Hughes Medical Institute; the Max Planck Institute for the Science of Human History; the University of California, Santa Cruz; Pennsylvania State University; the University of New Mexico; the University of São Paulo and other institutions in Argentina, Australia, Belize, Brazil, Chile, the European Union, Peru and the United States.

The researchers obtained official permits to excavate and conduct analysis on ancient human remains and consulted with local governmental agencies and indigenous communities.

Clovis link in the oldest Central and South Americans

A distinctive DNA type associated with the Clovis culture was found in Chile, Brazil and Belize 11,000 to 9,000 years ago.

“A key discovery was that a Clovis culture-associated individual from North America dating to around 12,800 years ago shares distinctive ancestry with the oldest Chilean, Brazilian and Belizean individuals,” said co-lead author Cosimo Posth of the Max Planck Institute for the Science of Human History. “This supports the hypothesis that the expansion of people who spread the Clovis culture in North America also reached Central and South America.”

However, the Clovis culture-associated lineage is missing in present-day South Americans and in ancient samples that are less than 9,000 years old.

“This is our second key discovery,” said co-senior author David Reich, professor of genetics at Harvard Medical School and a Howard Hughes Medical Institute investigator. “We have shown that there was a continent-wide population replacement that began at least 9,000 years ago.”

After the population replacement, there was striking genetic continuity between ancient individuals dating to up to 9,000 years ago and modern people from multiple South American regions. This contrasts with West Eurasia and Africa, where there are few places with such long-standing continuity.

This visual abstract depicts the findings of Posth et al., who conducted a large-scale analysis of ancient genomes from Central and South America yields insights into the peopling of the Americas, including four southward migration events and notable population continuity in much of South America after arrival. Credit: Posth et al./Cell

California Channel Island-associated ancestry in the Andes

The second previously unknown spread of people revealed itself in an analysis showing that ancient Californians from the Channel Islands have a distinctive shared ancestry with groups that became widespread in the southern Peruvian Andes by at least 4,200 years ago.

The researchers say this is unlikely to reflect population spread specifically from the Channel Islands into South America. Instead, they hypothesize that the connection between these regions is the result of expansions of people that occurred thousands of years earlier, and that such ancestry became more widespread in the Andes after subsequent events within South America.

“It could be that this ancestry arrived in South America thousands of years before and we simply don’t have earlier individuals showing it,” said Nathan Nakatsuka, a research assistant in the Reich lab at Harvard Medical School and co-lead author of the study. “There is archaeological evidence that the population in the Central Andes area greatly expanded after around 5,000 years ago. Spreads of particular subgroups during these events may be why we detect this ancestry afterward.”

The promise of ancient DNA research in the Americas

The researchers emphasize that their study gives only a glimpse of the discoveries that may come through future work.

To learn about the initial movements of people into Central and South America, they say, it would be necessary to obtain ancient DNA from individuals dating to before 11,000 years ago.

Even for the period between 11,000 and 3,000 years ago that this study focused on, the picture is far from complete.

“We lacked ancient data from Amazonia, northern South America and the Caribbean, and thus cannot determine how individuals in these regions relate to the ones we analyzed,” said Reich. “Filling in these gaps should be a priority for future work.”

“We are excited about the potential of research in this area,” said co-senior author Johannes Krause of the Max Planck Institute for the Science of Human History. “With future regionally-focused studies with large sample sizes, we could realize the potential of ancient DNA to reveal how the human diversity of this region came to be the way it is today.”


Explore further:
First peoples: Study finds two ancient ancestries ‘reconverged’ with settling of South America

More information:
Cell, Posth et al.: “Reconstructing the Deep Population History of Central and South America” DOI: 10.1016/j.cell.2018.10.027 , https://www.cell.com/cell/fulltext/S0092-8674(18)31380-1


Related Stories



Team finds oldest weapons ever discovered in North America



October 24, 2018

Texas A&M University researchers have discovered what are believed to be the oldest weapons ever found in North America: ancient spear points that are 15,500 years old. The findings raise new questions about the settlement …

Recommended for you



Tiny, ancient fossil shows evidence of the breath of life



November 7, 2018

An international team of scientists from Leicester, Yale, Oxford and London has discovered a rare and exceptionally well-preserved tiny crustacean in 430 million-years-old rocks in Herefordshire, UK. The fossil is a new species …

1 comment


Adjust slider to filter visible comments by rank

Display comments: newest first

Continue Reading
Advertisement
Click to comment

You must be logged in to post a comment Login

Leave a Reply

Science

Scientists acknowledge key errors in study of how fast the oceans are warming

The Azeri Times

Published

on

A major study claimed the oceans were warming much faster than previously thought. But researchers now say they can’t necessarily make that claim.



The sun sets over sea ice floating on the Victoria Strait along the Northwest Passage in the Canadian Arctic Archipelago during the summer of 2017. (AP Photo/David Goldman)

Chris Mooney

Reporter covering climate change, energy and the environment.

Brady Dennis

Reporter focusing on environmental policy and public health issues

Scientists behind a major study that claimed the Earth’s oceans are warming faster than previously thought now say their work contained inadvertent errors that made their conclusions seem more certain than they actually are.

Two weeks after the high-profile study was published in the journal Nature, its authors have submitted corrections to the publication. The Scripps Institution of Oceanography, home to several of the researchers involved, also noted the problems in the scientists’ work and corrected a news release on its website, which previously had asserted that the study detailed how the Earth’s oceans “have absorbed 60 percent more heat than previously thought.”

“Unfortunately, we made mistakes here,” said Ralph Keeling, a climate scientist at Scripps, who was a co-author of the study. “I think the main lesson is that you work as fast as you can to fix mistakes when you find them.”

The central problem, according to Keeling, came in how the researchers dealt with the uncertainty in their measurements. As a result, the findings suffer from too much doubt to definitively support the paper’s conclusion about just how much heat the oceans have absorbed over time.

The central conclusion of the study — that oceans are retaining ever more energy as more heat is being trapped within Earth’s climate system each year — is in line with other studies that have drawn similar conclusions. And it hasn’t changed much despite the errors. But Keeling said the authors’ miscalculations mean there is actually a much larger margin of error in the findings, which means researchers can weigh in with less certainty than they thought.

“I accept responsibility for what happened because it’s my role to make sure that those kind of details got conveyed,” Keeling said.

The study’s lead author was Laure Resplandy of Princeton University. Other researchers were with institutions in China, Paris, Germany and the U.S. National Center for Atmospheric Research and Geophysical Fluid Dynamics Laboratory.

“Maintaining the accuracy of the scientific record is of primary importance to us as publishers and we recognize our responsibility to correct errors in papers that we have published,” Nature said in a statement to The Post. “Issues relating to this paper have been brought to Nature’s attention and we are looking into them carefully. We take all concerns related to papers we have published very seriously and will issue an update once further information is available.”

The original study, which appeared on Oct. 31, derived a new method for measuring how much heat is being absorbed by the oceans. Essentially, the authors measured the volume of gases, specifically oxygen and carbon dioxide, that have escaped the ocean in recent decades and headed into the atmosphere as it heats up. They found that the warming “is at the high end of previous estimates” and suggested that as a result, the rate of global warming itself could be more accelerated.

The results, wrote the authors, may suggest there is less time than previously thought to curb greenhouse gas emissions. The study drew considerable media attention, including from The Post.

However, not long after publication, an independent Britain-based researcher named Nicholas Lewis published a lengthy blog post saying he had found a “major problem” with the research.

“So far as I can see, their method vastly underestimates the uncertainty,” Lewis said in an interview Tuesday, “as well as biasing up significantly, nearly 30 percent, the central estimate.”

Lewis added that he tends “to read a large number of papers, and, having a mathematics as well as a physics background, I tend to look at them quite carefully, and see if they make sense. And where they don’t make sense — with this one, it’s fairly obvious it didn’t make sense — I look into them more deeply.”

Lewis has argued in past studies and commentaries that climate scientists are predicting too much warming because of their reliance on computer simulations, and that current data from the planet itself suggests global warming will be less severe than feared.

It isn’t clear whether the authors agree with all of Lewis’s criticisms, but Keeling said “we agree there were problems along the lines he identified.”

Paul Durack, a research scientist at the Lawrence Livermore National Laboratory in California, said promptly acknowledging the errors in the study “is the right approach in the interests of transparency.”

But he added in an email, “This study, although there are additional questions that are arising now, confirms the long known result that the oceans have been warming over the observed record, and the rate of warming has been increasing,” he said.

Gavin Schmidt, head of the NASA Goddard Institute for Space Studies, followed the growing debate over the study closely on Twitter and said that measurements about the uptake of heat in the oceans have been bedeviled with data problems for some time — and that debuting new research in this area is hard.

“Obviously you rely on your co-authors and the reviewers to catch most problems, but things still sometimes slip through,” Schmidt wrote in an email.

Schmidt and Keeling agreed that other studies also support a higher level of ocean heat content than the Intergovernmental Panel on Climate Change, or IPCC, saw in a landmark 2013 report.

Overall, Schmidt said, the episode can be seen as a positive one.

“The key is not whether mistakes are made, but how they are dealt with — and the response from Laure and Ralph here is exemplary. No panic, but a careful reexamination of their working — despite a somewhat hostile environment,” he wrote.

“So, plus one for some post-publication review, and plus one to the authors for reexamining the whole calculation in a constructive way. We will all end up wiser.”

Continue Reading

Science

Russia unveils NUCLEAR spaceship poised for groundbreaking INTERSTELLAR missions

The Azeri Times

Published

on

Russia unveils NUCLEAR spaceship poised for groundbreaking INTERSTELLAR missions


RUSSIA’s Space Agency, Roscosmos, has unveiled a nuclear powered spaceship designed for groundbreaking interplanetary and interstellar flights.

space news, space, NASA, mars mission, interstellar, roscosmos, russia space, space, spaceship, spacecraft

Russia’s Space Agency, Roscosmos, has unveiled a nuclear powered spaceship (Image: Roscosmos/Getty)

When discussing the possibility of interstellar travel, some scientists tend to scoff at the idea because of the enormous distances that separate the stars. However, Roscosmos claims the craft will be able to make flights into deep space, thanks to the use of nuclear power. Video released on the Roscomos page on Facebook shows the concept design of the craft.

From past descriptions, the concept design includes a gas-cooled fission reaction that powers a generator, which in turn feeds a plasma thruster.

Vladimir Koshlakov, who heads Moscow’s Keldysh Research Centre told local media a mission to Mars will be able “in the very near future but that is not the aim in itself”.

He noted: “Our engines can be the foundation for a whole range of space missions that currently seem like science fiction.”

The Keldysh Research Centre, responsible for developing the Katyusha rocket launched during World War 2, has been working on the “unique” propulsion system since 2009.

space news, space, NASA, mars mission, interstellar, roscosmos, russia space, space, spaceship, spacecraft

Video released on the Roscomos page on Facebook shows the concept design of the craft (Image: Roscosmos)

Mr Koshlakov did not name a date for when the system will be ready but he suggested it “will surpass existing level of technological and scientific development”.

He added: “Reusability is the priority.

“We must develop engines that do not need to be fine-tuned or repaired more than once every ten flights.

“Also, 48 hours after the rocket returns from space, it must be ready to go again.

space news, space, NASA, mars mission, interstellar, roscosmos, russia space, space, spaceship, spacecraft

Vladimir Koshlakov a mission to Mars will be able “in the very near future but that is not the aim (Image: Getty)

“This is what the market demands.”

Asked whether he might be surpassed by other companies, such as Elon Musk’s SpaceX, which is planning its own mission to Mars, Mr Koshlakov firmly denied.

He said: “Elon Musk is using the existing tech, developed a long time ago.

“He is a businessman: he took a solution that was already there, and applied it successfully.

“Notably, he is also doing his work with help from the government.”

Continue Reading

Science

Menu for astronauts in space includes variety, comforts of home

The Azeri Times

Published

on

Menu for astronauts in space includes variety, comforts of home

In this Dec. 21, 2015 photo, Expedition 46 Commander Scott Kelly participates in a spacewalk outside the International Space Station. NASA scientists are always working to come up with better meals for astronauts living in space, where the body starts to lose bone and muscle mass. (NASA via AP file)

8035293

Neil Armstrong may have taken that first small step for man onto the moon, but it was John Glenn who took the first slurp of applesauce for humankind.

Until he ate while orbiting Earth in 1962, scientists at NASA weren’t sure humans could swallow and digest food while in space. Luckily, he chowed down in zero gravity with no trouble. Today’s astronauts sometimes spend months at a time living in the International Space Station, so they’d get pretty hungry without a few snacks!

Of course, while the human body is happy to take in a meal while hovering 250 miles above Earth, the process of cooking and eating food isn’t exactly the same as it is back home. That’s why NASA scientists are working hard to perfect astronaut menus. A healthy diet is even more crucial for space travelers than it is here on the surface, because spending time in space makes your body start to lose bone and muscle mass. NASA has to figure out how to send food up in a rocket, store it for as long as possible and make sure it delivers a perfect balance of nutrients — and it has to keep astronauts from getting bored, too!

“Imagine trying to eat the same food for every meal for six months. You may get tired of the food and eat less than you need to maintain weight, health and performance. That’s why we have to make sure there’s a large variety of healthy food available for the astronauts to make choices,” says F. Ryan Dowdy, ISS food system manager at NASA’s Johnson Space Center in Houston, Texas.

Astronauts have about 200 food items to pick from. According to Dowdy, a lot of the options are surprisingly similar to meals we eat on Earth.

“Whether it’s macaroni and cheese or chocolate pudding cake, it’s important for the astronauts when eating to be reminded of home,” he says. “Food can be an important psychological comfort in the stressful environment of space.”

It’s the preparation that’s unique: Food often has to sit in storage for six months before it even goes into space — and last for weeks or months at a time once it’s up there — so NASA designs everything with a shelf life of at least two years. Macaroni and cheese is freeze-dried (meaning that most of the moisture is removed, which makes it safe to store at room temperature), and astronauts add hot water to it on the space station. Chocolate pudding cake is preserved similarly to canned food, but NASA puts it in a flexible pouch so it takes up less space.

Some Earth foods are perfectly fit for zero-gravity consumption. Tortillas, for example, are a great alternative to bread — they last a long time in storage, and they don’t form crumbs that float around and get caught in important parts of the ship. Astronauts can request small quantities of fresh fruits and vegetables whenever NASA sends supplies up, but for the most part, they’re eating various combinations of super-durable stored foods.

As NASA looks to the future of spaceflight — with missions to Mars, and perhaps even farther — the agency has to design even more durable food. It takes about eight months to get to Mars, and astronauts will have to bring food for the journey home, too. Dowdy says NASA is working to extend the shelf life of its foods to around five years, but experiments in space farming are also part of the plan.

Astronauts on the ISS are able to farm plants such as lettuce in small quantities, but Dowdy says it will take some time before this is a sustainable source of calories.

He thinks 3D printed treats may also be on the menu someday soon. One thing is for sure: It’s going to take a lot of scientific know-how to feed the space explorers of the future.

21702517

Continue Reading
Advertisement
Oil extends slide from 7 percent slump the day before as outlook darkens
Business51 mins ago

Oil extends slide from 7 percent slump the day before as outlook darkens

Business51 mins ago

1.1 million Marylanders expected to travel for Thanksgiving

Business52 mins ago

Japan’s Economy Shrank in July-September as Trade Falls

Business52 mins ago

Mega Millions winning numbers for 11/13/2018; jackpot $106 million

Chick-fil-A Launches Nationwide Delivery Service to Bring Chicken Straight to Your Door
Business52 mins ago

Chick-fil-A Launches Nationwide Delivery Service to Bring Chicken Straight to Your Door

Business52 mins ago

Video shows McDonald’s drive-thru customer attack manager over missing ketchup, police say

Business52 mins ago

What Denver learned during its failed 14-month courtship of Amazon

Business52 mins ago

Apple Shares Down 5%, Now What?

Exclusive: Snap reveals US subpoenas on IPO disclosures
Business52 mins ago

Exclusive: Snap reveals US subpoenas on IPO disclosures

Amazon Fire TV Stick 4K Now on Sale in India, New Alexa Voice Remote Also Available
Technology52 mins ago

Amazon Fire TV Stick 4K Now on Sale in India, New Alexa Voice Remote Also Available

Technology52 mins ago

Thunderlord and Heavy Machine Guns are Back in Destiny 2

Essential’s $149 magnetic dongle will bring back your headphone jack
Technology52 mins ago

Essential’s $149 magnetic dongle will bring back your headphone jack

Four Google travel apps you’ve somehow lived without
Technology52 mins ago

Four Google travel apps you’ve somehow lived without

Microsoft resumes rollout of Windows 10 version 1809, promises quality changes
Technology52 mins ago

Microsoft resumes rollout of Windows 10 version 1809, promises quality changes

Start ‘Em, Sit ‘Em Week 11: Wide Receivers
Sport52 mins ago

Start ‘Em, Sit ‘Em Week 11: Wide Receivers

After Draymond Green-Kevin Durant spat, Steve Kerr’s demeanor speaks volumes about state of Warriors
Sport52 mins ago

After Draymond Green-Kevin Durant spat, Steve Kerr’s demeanor speaks volumes about state of Warriors

Sport52 mins ago

NFL must learn from Rams vs. Chiefs blunder in Mexico City for future international games

PBC, Fox announce four months of fights including Keith Thurman’s return and Errol Spence Jr. vs. Mikey Garcia
Sport52 mins ago

PBC, Fox announce four months of fights including Keith Thurman’s return and Errol Spence Jr. vs. Mikey Garcia

Corruption4 weeks ago

UK aims at shady Azerbaijani money – but is it missing the target?

Is the post office open today on Veterans Day (11/12/2018)? Will there be mail, UPS or FedEx delivery?
Politics2 days ago

Is the post office open today on Veterans Day (11/12/2018)? Will there be mail, UPS or FedEx delivery?

Politics4 weeks ago

Political émigré who returned home to visit critically ill father arrested on fraudulent drug-related charges

Karabakh4 weeks ago

No compensation for families of Azerbaijani soldiers killed in Karabakh

Sport4 weeks ago

Barcelona’s Turkish midfielder Turan could be jailed for 12 years

Military4 weeks ago

Azerbaijan Air Force conducts Drill to improve Air Defense capabilities

Georgia3 weeks ago

Azerbaijan should not fear Salome Zurabishvili

Azerbaijan3 weeks ago

Number of abortions among minors in Azerbaijan triples in just one year

Caucasus3 weeks ago

Sex-shops in the South Caucasus: there is sex, but no shops

Society3 weeks ago

Subsistence minimum in Azerbaijan to increase by 4 dollars

Business1 week ago

Papa Gino’s closes dozens of locations this weekend

Business1 week ago

Trump will punish everyone for Iran, except Azerbaijan

Opposition1 week ago

Exiled Azerbaijanis protest against arrest of Azad Hasanov

Technology1 week ago

Smash Ultimate’s DLC roster has been finalized

Business1 week ago

Cruise descends into ‘pure chaos’ as ship loses its balance

Azerbaijan1 week ago

Former USSR commemorates the 13 million victims of Stalinist political repression

Victim in fatal stabbing at Seattle Center had restraining order against suspect
Politics1 week ago

Victim in fatal stabbing at Seattle Center had restraining order against suspect

Amazon Prime Membership Loses Some Value
Business1 week ago

Amazon Prime Membership Loses Some Value

Trending

© Azeri Times - All rights reserved. Republication or redistribution of the site's materials is permitted only with a mandatory reference to www.azeritimes.com. Email: info@azeritimes.com