Connect with us

Technology

DNA from an unknown human ancestor that bred with Denisovans still exists among people today 

Published

on

dna from an unknown human ancestor that bred with denisovans still exists among people today

DNA from an unknown ancient ancestor of humans that once bred with Denisovans still exists among the genomes of people today, a study has revealed. 

The different branches of the human family tree have interbred and swapped genes — a processes known as ‘introgression’ — on numerous occasions.

DNA sequencing of Neanderthals and Denisovans have provided insights into the nature of the interbreeding events and the moment of ancient humans. 

For example, around 50,000 years ago, a group of humans migrated out of Africa to Eurasia, where they interbred with Neanderthals and swapped DNA fragments.

Experts from the US found that some three per cent of the Neanderthal genome came from interbreeding with another ancient human group 300,000 years ago.

DNA from an unknown human ancestor that bred with Denisovans some 300,000 years ago still exists among the genomes of people today, a study has revealed (stock image)

DNA from an unknown human ancestor that bred with Denisovans some 300,000 years ago still exists among the genomes of people today, a study has revealed (stock image)

DNA from an unknown human ancestor that bred with Denisovans some 300,000 years ago still exists among the genomes of people today, a study has revealed (stock image)

In their paper, computational biologist Adam Siepel of the Cold Spring Harbor Laboratory and colleagues developed a special algorithm for analysing genomes.

This software can identify segments of DNA that originated form other species — even in cases where the gene flow was minimal, took place thousands of years ago and came from an unknown or unclear source.

The work is exciting, Professor Siepel said, as ‘it demonstrates what you can learn about deep human history by jointly reconstructing the full evolutionary history of a collection of sequences from modern humans and archaic hominins.’

The researchers used the algorithm to look at genomes from two Neanderthals, a Denisovan and two African humans.

Alongside finding that a small proportion of the Neanderthal genome came from ancient humans, the team also determined that one per cent of the Denisovan genome appears to have come from an unknown and more distant species.

Moreover, up to 15 per cent of this ‘super-archaic’ genetic material has likely been passed down into modern humans who are alive today, the researchers said.

While it is not clear exactly from which species these fragments of DNA originated, the team suspect that they may have come from Homo Erectus, an ancient hominin species that first emerged around two million years ago.

‘This new algorithm that Melissa has developed — ARGweaver-D — is able to reach back further in time than any other computational method I’ve seen,’ commented Professor Siepel.

‘It seems to be especially powerful for detecting ancient introgression.’

Alongside finding that a small proportion of the Neanderthal genome (red) came from ancient humans, the team also determined that one per cent of the Denisovan genome (blue) appears to have come from an unknown and more distant species (orange). Moreover, up to 15 per cent of this 'super-archaic' genetic material has likely been passed down into modern humans who are alive today (green), the researchers said

Alongside finding that a small proportion of the Neanderthal genome (red) came from ancient humans, the team also determined that one per cent of the Denisovan genome (blue) appears to have come from an unknown and more distant species (orange). Moreover, up to 15 per cent of this 'super-archaic' genetic material has likely been passed down into modern humans who are alive today (green), the researchers said

 Alongside finding that a small proportion of the Neanderthal genome (red) came from ancient humans, the team also determined that one per cent of the Denisovan genome (blue) appears to have come from an unknown and more distant species (orange). Moreover, up to 15 per cent of this ‘super-archaic’ genetic material has likely been passed down into modern humans who are alive today (green), the researchers said

The findings add to the many previously known cases of gene flow between ancient humans and their relatives.

Moreover, given the number of introgression events, it seems likely that interbreeding occurred whenever two groups overlapped in time and space, the researchers commented.

The ARGweaver-D algorithm may also prove a useful tool to study other species which have undergone significant interbreeding episodes — such as occurs among wolves and dogs.

The full findings of the study were published in the journal PLOS Genetics.

WHO WERE THE DENISOVANS?

The Denisovans are an extinct species of human that appear to have lived in Siberia and even down as far as southeast Asia.

Although remains of these mysterious early humans have only been discovered at one site – the Denisova Cave in the Altai Mountains in Siberia, DNA analysis has shown they were widespread.

DNA from these early humans has been found in the genomes of modern humans over a wide area of Asia, suggesting they once covered a vast range.

DNA analysis of a fragment of pinky finger bone in 2010, (pictured) which belonged to a young girl, revealed the Denisovans were a species related to, but different from, Neanderthals.

DNA analysis of a fragment of pinky finger bone in 2010, (pictured) which belonged to a young girl, revealed the Denisovans were a species related to, but different from, Neanderthals.

DNA analysis of a fragment of pinky finger bone in 2010, (pictured) which belonged to a young girl, revealed the Denisovans were a species related to, but different from, Neanderthals.

They are thought to have been a sister species of the Neanderthals, who lived in western Asia and Europe at around the same time.

The two species appear to have separated from a common ancestor around 200,000 years ago, while they split from the modern human Homo sapien lineage around 600,000 years ago. 

Bone and ivory beads found in the Denisova Cave were discovered in the same sediment layers as the Denisovan fossils, leading to suggestions they had sophisticated tools and jewellery.

DNA analysis of a fragment of a fifth digit finger bone in 2010, which belonged to a young girl, revealed they were a species related to, but different from, Neanderthals.

Later genetic studies suggested that the ancient human species split away from the Neanderthals sometime between 470,000 and 190,000 years ago. 

Anthropologists have since puzzled over whether the cave had been a temporary shelter for a group of these Denisovans or it had formed a more permanent settlement.

DNA from molar teeth belonging to two other individuals, one adult male and one young female, showed they died in the cave at least 65,000 years earlier.

Other tests have suggested the tooth of the young female could be as old as 170,000 years.

A third molar is thought to have belonged to an adult male who died around 7,500 years before the girl whose pinky was discovered.

<!—->Advertisement

Powered by: Daily Mail

Continue Reading
Advertisement
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Technology

Twitter goes down for more than an hour leaving thousands of users unable to access the platform

Published

on

By

twitter goes down for more than an hour leaving thousands of users unable to access the platform

More than 50,000 Twitter users were unable to access the website and app versions of the social media platform Thursday morning due to a worldwide outage.

Down Detector showed the outage started around 9:30am ET and was plaguing parts of the US, Europe and Asia.

Many users were met with an ‘error message’ when logging in, along with a blank news feed that only reads ‘try again’ and disabled features – all of which hindered their ability to share tweets. 

The peak of the outage hit around 10am ET, but much of the service was restored around 10:45am ET – some Twitter users may still be experiencing issues. 

More than 50,000 Twitter users were unable to access the website and app versions of the social media platform Thursday morning due to a worldwide outage. Down Detector showed the outage started around 9:30am ET and was plaguing parts of the US, Europe and Asia

More than 50,000 Twitter users were unable to access the website and app versions of the social media platform Thursday morning due to a worldwide outage. Down Detector showed the outage started around 9:30am ET and was plaguing parts of the US, Europe and Asia

More than 50,000 Twitter users were unable to access the website and app versions of the social media platform Thursday morning due to a worldwide outage. Down Detector showed the outage started around 9:30am ET and was plaguing parts of the US, Europe and Asia 

Typically when one social media site experiences an outage, users flock to Twitter to share their frustrations or ask if anyone else is having problems.

But when Twitter went down, the world may be in a frenzy.

DailyMail.com has reached out to Twitter for comment and has yet to receive a response. 

Down Detector, a platform that monitors website and online service outages, is one of the only places the public can go to check on the outage when Twitter is down. 

The outage appeared around 9:30am and is located in the US, the UK and Japan - other countries in Europe, Asia and South American are also reporting issues

The outage appeared around 9:30am and is located in the US, the UK and Japan - other countries in Europe, Asia and South American are also reporting issues

The outage appeared around 9:30am and is located in the US, the UK and Japan – other countries in Europe, Asia and South American are also reporting issues

Many users were met with an 'error message' when logging in, along with a blank news feed that only reads 'try again' and disabled features - all of which hindered their ability to share tweets

Many users were met with an 'error message' when logging in, along with a blank news feed that only reads 'try again' and disabled features - all of which hindered their ability to share tweets

Many users were met with an ‘error message’ when logging in, along with a blank news feed that only reads ‘try again’ and disabled features – all of which hindered their ability to share tweets 

The majority of the outage was plaguing the website, but users reported issues with the iOS and Android apps. 

Down Detector’s outage map showed a number of major cities in the US as red, including Seattle, San Francisco, Washington  DC and New York City.

Twitter also went down in Japan, parts of India and Indonesia, along with countries in Europe.

Users shared their frustrations on Down Detector about Twitter going down so early in the day.

Users have shared their frustrations on Down Detector about Twitter going down so early in the day. One user joke that without the site, all they can do is look at the wall

Users have shared their frustrations on Down Detector about Twitter going down so early in the day. One user joke that without the site, all they can do is look at the wall

Users have shared their frustrations on Down Detector about Twitter going down so early in the day. One user joke that without the site, all they can do is look at the wall

Another took this time to take a dig at liberals: 'I hope they fix it by 11:30AM when all the white liberals start rolling out of bed... they have some very important hashtags to tweet out today to save all the helpless minorities they are trying to rescue'

Another took this time to take a dig at liberals: 'I hope they fix it by 11:30AM when all the white liberals start rolling out of bed... they have some very important hashtags to tweet out today to save all the helpless minorities they are trying to rescue'

Another took this time to take a dig at liberals: ‘I hope they fix it by 11:30AM when all the white liberals start rolling out of bed… they have some very important hashtags to tweet out today to save all the helpless minorities they are trying to rescue’

One user joked that without the site, all they can do is look at the wall.

Another took this time to take a dig at liberals: ‘I hope they fix it by 11:30AM when all the white liberals start rolling out of bed… they have some very important hashtags to tweet out today to save all the helpless minorities they are trying to rescue.’

The peak of the outage was around 10am ET, but service was coming back shortly after, with reports decreasing about 45 minutes later.

This post first appeared on dailymail.co.uk

Continue Reading

Technology

Twitter is DOWN! Thousands of users across the world are unable to access the social media platform

Published

on

By

twitter is down thousands of users across the world are unable to access the social media platform

 If you are having issues with Twitter, you are not the only one – more than 40,000 users across the world are experiencing problems with the social media platform.

The social media site is experiencing an outage that seems to be hitting the website and apps on both iOS and Android.

The outage appeared around 9:30am and is located in the US, the UK and Japan – other countries in Europe, Asia and South American are also reporting issues.

Many users have been met with an ‘error message’ when logging in, along with a blank news feed. 

If you are having issues with Twitter, you are not the only one. The social media site is experiencing an outage that seems to be hitting the website and apps on both iOS and Android

If you are having issues with Twitter, you are not the only one. The social media site is experiencing an outage that seems to be hitting the website and apps on both iOS and Android

Typically when one social media site experiences an outage, users flock to Twitter to share their frustrations or ask if anyone else is having problems.

But with Twitter down, the world may be in a frenzy.

Down Detector, a platform that monitors website and online service outages, is one of the only places the public can go to check on the outage.

The outage report shows more than 48,000 people have reported issues with Twitter, which started flowing in around 9:30am ET.

The outage appeared around 9:30am and is located in the US, the UK and Japan - other countries in Europe, Asia and South American are also reporting issues. Many users have been met with an 'error message' when logging in, along with a blank news feed

The outage appeared around 9:30am and is located in the US, the UK and Japan – other countries in Europe, Asia and South American are also reporting issues. Many users have been met with an ‘error message’ when logging in, along with a blank news feed

Approximately 49 percent are experiencing issues with the website, 35 percent noted problems with Twitter on an iOS devices and 15 percent on the Android app.

Down Detector’s outage map shows a number of major cities in the US as red, including Seattle, San Francisco, Washington  DC and New York City.

Twitter has also gone down in Japan, parts of India and Indonesia.

This post first appeared on dailymail.co.uk

Continue Reading

Technology

Nuclear fusion reactor could be producing electricity within a decade 

Published

on

By

nuclear fusion reactor could be producing electricity within a decade

A tennis court-sized nuclear fusion reactor being developed in the US could be producing electricity within a decade, backers claim.  

The SPARC nuclear fusion reactor, a joint project involving Massachusetts Institute of Technology, is expected to begin construction on June 21 next year and take three or four years until completion.

It is hoped that SPARC will demonstrate energy gain from fusion for the first time in history by 2025, and be producing fusion energy to generate electricity to power nearby cities within 10 years. 

Nuclear fusion power works by colliding heavy hydrogen atoms to form helium, releasing vast amounts of energy, mimicking the process that occurs naturally in the centre of stars like our Sun. 

Scroll down for video 

SPARC, which is on track to begin construction in 2021 and demonstrate net energy gain from fusion for the first time in history by 2025. Pictured, artists' impression of the reactor with a human for scale

SPARC, which is on track to begin construction in 2021 and demonstrate net energy gain from fusion for the first time in history by 2025. Pictured, artists’ impression of the reactor with a human for scale

Fusion could eventually combat climate change by replacing energy sources that emit greenhouse gases, such as coal and gas. 

Fusion also provides cheap, clean and safe energy without radioactive waste, or the risk of meltdown. 

SPARC will pave the way for the first commercially viable fusion power plant, called ARC. 

MIT said limitations imposed by the Covid-19 pandemic have only slightly slowed progress on SPARC and researchers are back in the labs under new operating guidelines. 

‘The work is progressing smoothly and on track,’ said MIT, which is working with Cambridge, Massachusetts-based company Commonwealth Fusion Systems (CFS) on SPARC. 

A fusion power plant could provide clean, carbon-free energy with an essentially unlimited fuel supply. From the point of view of electrical power generation, the fusion device is just another heat source that could be used in a conventional thermal conversion cycle.

A fusion power plant could provide clean, carbon-free energy with an essentially unlimited fuel supply. From the point of view of electrical power generation, the fusion device is just another heat source that could be used in a conventional thermal conversion cycle. 

‘No unexpected impediments or surprises have shown up, and the remaining challenges appear to be manageable,’ it said in a statement.  

SPARC is set to be the first experimental device ever to achieve a ‘burning plasma’ – a self-sustaining fusion reaction in which different isotopes of the element hydrogen fuse together to form helium, without the need for any further input of energy. 

When deuterium and tritium nuclei – which can be found in hydrogen – fuse, they form a helium nucleus, a neutron and a lot of energy.

This is done by heating the fuel to temperatures in excess of 270,000,000°F (150,000,000°C) and forming a hot plasma – a gaseous soup of subatomic particles – held in place by magnets.

The strong magnetic fields are used to keep the plasma away from the reactor’s walls, so that it doesn’t cool down and lose its energy potential.

Fusion power works by colliding heavy hydrogen atoms to form helium - releasing vast amounts of energy in the process, as occurs naturally in the centre of stars

Fusion power works by colliding heavy hydrogen atoms to form helium – releasing vast amounts of energy in the process, as occurs naturally in the centre of stars

These fields are produced by superconducting coils surrounding the vessel and by an electrical current driven through the plasma.    

Information gathered from the behaviour of burning plasma is ‘crucial’ for developing the next step – a working prototype of a practical, power-generating power plant, the SPARC team said. 

Once this is up and running, key information can be gained that will help pave the way to commercial, power-producing fusion devices. 

Fuel running these devices – the hydrogen isotopes deuterium and tritium – can be made available in virtually limitless supplies. 

Work on the first stage of the SPARC project is the development of the superconducting magnets that would allow smaller fusion systems to be built. 

Fusion power plants are set to reduce greenhouse gas emissions from the power-generation sector, which is one of the major sources of these emissions globally.    

SPARC is designed to achieve what is called a Q factor – a key parameter denoting the efficiency of a fusion plasma – of at least two.

This essentially means that twice as much fusion energy is produced as the amount of energy pumped in to generate the reaction. 

Fusion joins two light elements (with a low atomic mass number), forming a heavier element, to generate energy. Pictured, artist's illustration (stock image)

Fusion joins two light elements (with a low atomic mass number), forming a heavier element, to generate energy. Pictured, artist’s illustration (stock image)

If realised, SPARC would be the first time a fusion plasma of any kind has produced more energy than it consumed. 

Computer calculations and simulation tools show SPARC could actually achieve a Q ratio of 10 or more, MIT claims.

A series of papers authored by 47 researchers from 12 institutions have been published in Journal of Plasma Physics summarising progress on SPARC. 

Together, the papers outline the theoretical and empirical physics basis for the new fusion system before it starts construction next year. 

‘The MIT group is pursuing a very compelling approach to fusion energy,’ said Chris Hegna, a professor of engineering physics at the University of Wisconsin at Madison, who was not connected to this work. 

‘They realised the emergence of high-temperature superconducting technology enables a high magnetic field approach to producing net energy gain from a magnetic confinement system. 

Pictured, one of two 800-tonne vacuum vessel assembly tools, as captured by the artist Luca Zanier, involved in the construction of the much larger ITER Tokamak reactor now being built in France

Pictured, one of two 800-tonne vacuum vessel assembly tools, as captured by the artist Luca Zanier, involved in the construction of the much larger ITER Tokamak reactor now being built in France

‘This work is a potential game-changer for the international fusion program​.’ 

The SPARC design would achieve fusion performance comparable to that expected in the much larger ITER Tokamak now being built in France. 

The Provence-based ITER project is expected to begin delivering power in 2035 – several years later than SPARC if all goes to plan for the US team. 

‘We’re really focused on how you can get to fusion power as quickly as possible,’ CFS CEO Bob Mumgaard told the New York Times.

SPARC would be far smaller than ITER – about the size of a tennis court, compared with a soccer field, Mumgaard said. 

High power in a small size is made possible by advances in superconducting magnets that allow for a much stronger magnetic field to confine the hot plasma, MIT said. 

DIFFERENCE BETWEEN NUCLEAR FUSION AND NUCLEAR FISSION 

 Both are nuclear processes, in that they involve nuclear forces to change the nucleus of atoms.

Fusion joins two light elements (with a low atomic mass number), forming a heavier element.

For fusion to occur, hydrogen atoms are placed under high heat and pressure until they fuse together.

Meanwhile, fission splits a heavy element (with a high atomic mass number) into fragments.

In both cases, energy is freed because the mass of the remaining nucleus is smaller than the mass of the reacting nuclei.

The reason why opposite processes release energy can be understood by examining the binding energy per nucleon curve. Both fusion and fission reactions shift the size of the reactant nuclei towards higher bounded nuclei.

Source: International Atomic Energy Agency  

Advertisement

This post first appeared on dailymail.co.uk

Continue Reading

Trending

Copyright © 2020 DiazHub.