Tag: human

Bacteria On Space Station Likely From Germy Humans, Not Aliens

Living bacteria have been found on the outside of the International Space Station, a Russian cosmonaut told the state news agency TASS this week.

Anton Shkaplerov, who will lead Russia’s ISS crew in December, said that previous cosmonauts swabbed the station’s Russian segment during spacewalks and sent the samples back to Earth.

The samples came from places on the station that had accumulated fuel waste, as well as other obscure nooks and crannies.

Their tests showed that the swabs held types of bacteria that were not on the module when it originally launched into orbit, Shkaplerov says.

In his interview with TASS, Shkaplerov says the bacteria “have come from outer space and settled along the external surface“, a claim that sparked some media outlets to issue frenzied reports about aliens colonizing the space station.

For now, though, details about the swabbing experiment are thin on the ground.




Shkaplerov did not note whether the study has been vetted by a peer-reviewed journal, which means it’s unclear exactly when and how the full experiment was conducted, or how the team avoided any contamination from much more mundane bacteria on the cosmonauts or in the Earth-bound lab.

Interview requests with the Russian space agency were unanswered when this article went to press. Up in the vacuum of space, microbes have to deal with turbulent temperatures, cosmic radiation, and ultraviolet light.

But Earth is home to plenty of hardy organisms that can survive in extreme environments, like virtually indestructible tardigrades.

Sometimes, researchers intentionally send terrestrial contaminants, such as E. coli and rocks covered in bacteria, into space to see how it will react.

And TASS reports that on a previous ISS mission, bacteria accidentally hitched a ride to the station on tablet PCs and other materials.

Scientists sent these objects up to see how they would fare in space, and the freeriding organisms managed to infiltrate the outside of the station.

They remained there for three years, braving temperatures fluctuating between -150 and 150 degrees Celsius.

 

These types of discoveries present concerns for scientists trying to limit the spread of human germs on other worlds.

NASA in particular has set strict limits on its interplanetary contamination.

Apollo astronauts were quarantined when they returned from their missions, for example, to prevent extraterrestrial germs from making their way out into the world.

And almost all equipment from Earth is sterilized before it heads skyward, either with extreme heat or an alcohol bath, depending on its intended destination.

These treatments are especially important for missions sent to Mars, which may have once hosted its own life-forms, leaving fossil traces in the rusty rocks.

But all bets may be off when and if we manage to send humans to explore Mars, writes The Planetary Society’s Emily Lakdawalla: “Once we’ve put humans on the surface, alive or dead, it becomes much, much harder to identify native Martian life.”

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The Origins Of Our Species Might Need A Rethink

On the outskirts of Beijing, a small limestone mountain named Dragon Bone Hill rises above the surrounding sprawl.

Along the northern side, a path leads up to some fenced-off caves that draw 150,000 visitors each year, from schoolchildren to grey-haired pensioners.

It was here, in 1929, that researchers discovered a nearly complete ancient skull that they determined was roughly half a million years old.

Dubbed Peking Man, it was among the earliest human remains ever uncovered, and it helped to convince many researchers that humanity first evolved in Asia.

Since then, the central importance of Peking Man has faded. Although modern dating methods put the fossil even earlier at up to 780,000 years old the specimen has been eclipsed by discoveries in Africa that have yielded much older remains of ancient human relatives.




Such finds have cemented Africa’s status as the cradle of humanity the place from which modern humans and their predecessors spread around the globe and relegated Asia to a kind of evolutionary cul-de-sac.

But the tale of Peking Man has haunted generations of Chinese researchers, who have struggled to understand its relationship to modern humans.

It’s a story without an ending,” says Wu Xinzhi, a palaeontologist at the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing.

They wonder whether the descendants of Peking Man and fellow members of the species Homo erectus died out or evolved into a more modern species, and whether they contributed to the gene pool of China today.

Keen to get to the bottom of its people’s ancestry, China has in the past decade stepped up its efforts to uncover evidence of early humans across the country.

It is reanalysing old fossil finds and pouring tens of millions of dollars a year into excavations. And the government is setting up a US$1.1-million laboratory at the IVPP to extract and sequence ancient DNA.

In its typical form, the story of Homo sapiens starts in Africa. The exact details vary from one telling to another, but the key characters and events generally remain the same. And the title is always ‘Out of Africa’.

In this standard view of human evolution, H. erectus first evolved there more than 2 million years ago.

Then, some time before 600,000 years ago, it gave rise to a new species: Homo heidelbergensis, the oldest remains of which have been found in Ethiopia.

About 400,000 years ago, some members of H. heidelbergensis left Africa and split into two branches: one ventured into the Middle East and Europe, where it evolved into Neanderthals; the other went east, where members became Denisovans a group first discovered in Siberia in 2010.

The remaining population of H. heidelbergensis in Africa eventually evolved into our own species, H. sapiens, about 200,000 years ago.

Then these early humans expanded their range to Eurasia 60,000 years ago, where they replaced local hominins with a minuscule amount of interbreeding.

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Working An Occasional Night Shift Could Kill You

Working an occasional night shift for a prolonged period could ultimately kill you, according to a major new study.

Researchers in the US looked at the medical records of about 189,000 women over a 24-year period and found a significant link between ‘rotating’ shift patterns, in which people alternate between night and day work, and coronary heart disease (CHD).

They suggested further work should be done to find out if shift patterns could be altered to reduce the risks.

Scientists have reported the adverse health effects of working night shifts before but the sheer size of this study underlines the extent of the problem.




Dr Celine Vetter, lead author of a paper in the Journal of the American Medical Association (JAMA), said: “There are a number of known risk factors for coronary heart disease, such as smoking, poor diet, lack of physical activity, and elevated body mass index. 

These are all critical factors when thinking how to prevent CHD. However, even after controlling for these risk factors, we still saw an increased risk of CHD associated with rotating shift work.

They found that those who worked three or more night shifts a month for a decade had a 15 to 18 per cent higher chance of getting the disease than those who did not have a rotating shift pattern  – an effect they described as “modest”.

They said their findings were applicable only to women as occasional shift work might affect men differently.

It is important to note that this is a modifiable risk factor, and changing shift schedules may have an impact on the prevention of CHD,” said Dr Vetter, an epidemiologist at Brigham and Women’s Hospital in Boston.

Our results are in line with other findings, yet, it is possible that different schedules might carry a different risk — and we have very little information on exact schedules — as well as work start and end times. 

We believe that the results from our study underline the need for future research to further explore the relationship between shift schedules, individual characteristics and coronary health to potentially reduce CHD risk.

The researchers used information from the US Nurses’ Health Study in which they reported everything from heart attacks to CHD-related chest pain. Fatalities from CHD were confirmed by death certificates.

Over the 24-year period of the study, more than 10,000 women developed the disease.

It has been suggested that changing shifts can disrupt people’s body clock, which operates on a rough 24-hour cycle.

Circadian misalignment – where the [the body’s natural rhythm is out of step] with behavioural cycles of activity, sleep and food intake – may be a key mechanism linking shift work to chronic disease, including cardiovascular disease,” the researchers wrote in the JAMA paper.

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Humans Are Still Evolving—And We Can Watch It Happen

Many people think evolution requires thousands or millions of years, but biologists know it can happen fast.

Now, thanks to the genomic revolution, researchers can actually track the population-level genetic shifts that mark evolution in action—and they’re doing this in humans.

Two studies presented at the Biology of Genomes meeting here last week show how our genomes have changed over centuries or decades, charting how since Roman times the British have evolved to be taller and fairer, and how just in the last generation the effect of a gene that favors cigarette smoking has dwindled in some groups.

Being able to look at selection in action is exciting,” says Molly Przeworski, an evolutionary biologist at Columbia University.

The studies show how the human genome quickly responds to new conditions in subtle but meaningful ways, she says. “It’s a game-changer in terms of understanding evolution.”




Evolutionary biologists have long concentrated on the role of new mutations in generating new traits. But once a new mutation has arisen, it must spread through a population.

Every person carries two copies of each gene, but the copies can vary slightly within and between individuals. Mutations in one copy might increase height; those in another copy, or allele, might decrease it.

If changing conditions favor, say, tallness, then tall people will have more offspring, and more copies of variants that code for tallness will circulate in the population.

With the help of giant genomic data sets, scientists can now track these evolutionary shifts in allele frequencies over short timescales.

Jonathan Pritchard of Stanford University in Palo Alto, California, and his postdoc Yair Field did so by counting unique single-base changes, which are found in every genome.

Such rare individual changes, or singletons, are likely recent, because they haven’t had time to spread through the population.

Because alleles carry neighboring DNA with them as they circulate, the number of singletons on nearby DNA can be used as a rough molecular clock, indicating how quickly that allele has changed in frequency.

Pritchard’s team analyzed 3000 genomes collected as part of the UK10K sequencing project in the United Kingdom. For each allele of interest in each genome, Field calculated a “singleton density score” based on the density of nearby single, unique mutations.

The more intense the selection on an allele, the faster it spreads, and the less time there is for singletons to accumulate near it. The approach can reveal selection over the past 100 generations, or about 2000 years.

Stanford graduate students Natalie Telis and Evan Boyle and postdoc Ziyue Gao found relatively few singletons near alleles that confer lactose tolerance—a trait that enables adults to digest milk—and that code for particular immune system receptors.

Among the British, these alleles have evidently been highly selected and have spread rapidly.

The team also found fewer singletons near alleles for blond hair and blue eyes, indicating that these traits, too, have rapidly spread over the past 2000 years, Field reported in his talk and on 7 May in the preprint server bioRxiv.org.

One evolutionary driver may have been Britain’s gloomy skies: Genes for fair hair also cause lighter skin color, which allows the body to make more vitamin D in conditions of scarce sunlight.

Or sexual selection could have been at work, driven by a preference for blond mates.

Other researchers praise the new technique.

This approach seems to allow much more subtle and much more common signals of selection to be detected,” says evolutionary geneticist Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

In a sign of the method’s power, Pritchard’s team also detected selection in traits controlled not by a single gene, but by tiny changes in hundreds of genes.

Among them are height, head circumference in infants, and hip size in females—crucial for giving birth to those infants.

By looking at the density of singletons flanking more than 4 million DNA differences, Pritchard’s team discovered that selection for all three traits occurred across the genome in recent millennia.

Joseph Pickrell, an evolutionary geneticist at New York Genome Center in New York City, has used a different strategy to put selection under an even keener microscope, detecting signs of evolution on the scale of a human lifetime.

He and Przeworski took a close look at the genomes of 60,000 people of European ancestry who had been genotyped by Kaiser Permanente in Northern California, and 150,000 people from a massive U.K. sequencing effort called the UK Biobank.

They wanted to know whether genetic variants change frequency across individuals of different ages, revealing selection at work within a generation or two.

The biobank included relatively few old people, but it did have information about participants’ parents, so the team also looked for connections between parental death and allele frequencies in their children.

In the parents’ generation, for example, the researchers saw a correlation between early death in men and the presence in their children (and therefore presumably in the parents) of a nicotine receptor allele that makes it harder to quit smoking.

Many of the men who died young had reached adulthood in the United Kingdom in the 1950s, a time when many British men had a pack-a-day habit.

In contrast, the allele’s frequency in women and in people from Northern California did not vary with age, presumably because fewer in these groups smoked heavily and the allele did not affect their survival.

As smoking habits have changed, the pressure to weed out the allele has ceased, and its frequency is unchanged in younger men, Pickrell explains.

My guess is we are going to discover a lot of these gene-by-environment effects,” Przeworski says.

Indeed, Pickrell’s team detected other shifts. A set of gene variants associated with late-onset menstruation was more common in longer-lived women, suggesting it might help delay death.

Pickrell also reported that the frequency of the ApoE4 allele, which is associated with Alzheimer’s disease, drops in older people because carriers died early.

We can detect selection on the shortest timeframe possible, an individual’s life span,” he says.

Signs of selection on short timescales will always be prey to statistical fluctuations.

But together the two projects “point to the power of large studies to understand what factors determine survival and reproduction in humans in present-day societies,” Pääbo says.

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According To Scientists, Europe Was The Birthplace Of Mankind And Not Africa

The history of human evolution has been rewritten after scientists discovered that Europe was the birthplace of mankind, not Africa.

Currently, most experts believe that our human lineage split from apes around seven million years ago in central Africa, where hominids remained for the next five million years before venturing further afield.

But two fossils of an ape-like creature which had human-like teeth have been found in Bulgaria and Greece, dating to 7.2 million years ago.

The discovery of the creature, named Graecopithecus freybergi, and nicknameded ‘El Graeco’ by scientists, proves our ancestors were already starting to evolve in Europe 200,000 years before the earliest African hominid.




An international team of researchers say the findings entirely change the beginning of human history and place the last common ancestor of both chimpanzees and humans – the so-called Missing Link – in the Mediterranean region.

At that time climate change had turned Eastern Europe into an open savannah which forced apes to find new food sources, sparking a shift towards bipedalism, the researchers believe.

This study changes the ideas related to the knowledge about the time and the place of the first steps of the humankind,” said Professor Nikolai Spassov from the Bulgarian Academy of Sciences.

Graecopithecus is not an ape. He is a member of the tribe of hominins and the direct ancestor of homo.”

The food of the Graecopithecus was related to the rather dry and hard savannah vegetation, unlike that of the recent great apes which are living in forests.  Therefore, like humans, he has wide molars and thick enamel.

To some extent this is a newly discovered missing link. But missing links will always exist , because evolution is infinite chain of subsequent forms. Probably  El Graeco’s face will resemble a great ape, with shorter canines.”

The team analysed the two known specimens of Graecopithecus freybergi: a lower jaw from Greece and an upper premolar tooth from Bulgaria.

Using computer tomography, they were able to visualise the internal structures of the fossils and show that the roots of premolars are widely fused.

The lower jaw, has additional dental root features, suggesting that the species was a hominid.

The species was also found to be several hundred thousand years older than the oldest African hominid, Sahelanthropus tchadensis which was found in Chad.

Professor David Begun, a University of Toronto paleoanthropologist and co-author of this study, added: “This dating allows us to move the human-chimpanzee split into the Mediterranean area.

During the period the Mediterranean Sea went through frequent periods of drying up completely, forming a land bridge between Europe and Africa and allowing apes and early hominids to pass between the continents.

The team believe that evolution of hominids may have been driven by dramatic environmental changes which sparked the formation of the North African Sahara more than seven million years ago and pushed species further North.

They found large amounts of Saharan sand in layers dating from the period, suggesting that it lay much further North than today.

Retired anthropologist and author Dr Peter Andrews, formerly at the Natural History Museum in London, said: “It is possible that the human lineage originated in Europe, but very substantial fossil evidence places the origin in Africa, including several partial skeletons and skulls.”

I would be hesitant about using a single character from an isolated fossil to set against the evidence from Africa.

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5 Cool Things DNA Testing Can Do

Genes are the foundation of our physiology. They contain the code that determines what we look like and how our bodies function.

Biologist James Watson and physicist Francis Crick realized our DNA molecules form a three-dimensional double helix in 1953. But DNA research dates back to the late 1860s, according to Nature Education.

Friedrich Miescher was the first to identify “nucleic acid” in our white blood cells; his 1869 finding was later named deoxyribonucleic acid, or DNA.




Others later defined the components that make up DNA molecules, identified RNA (ribonucleic acid, the other type of nucleic acid found in all cells along with DNA) and determined that although DNA differs in each species, it always maintains certain properties.

Those findings led to Watson and Crick’s conclusion, which paved the way for decades of DNA discoveries.

Today we use DNA tests to tell us about all kinds of things. Here are five cool things DNA testing can do:

Map your family tree

A DNA test could give you thousands of new relatives (although if they’re anything like ours, we’re not sure why you’d want them).

There are websites that offers to compare your DNA to those they already have on record in hopes of connecting you to unknown branches of your family tree.They can also tell you your genetic ethnicity.

Solve ancient mysteries

No one knew where Richard III, one of the most famous kings of England, was buried until his remains were discovered in a parking lot in Leicester.

The remains showed evidence of battle wounds and scoliosis, but scientists weren’t sure the skeleton was Richard III’s until DNA extracted from the bones was matched to Michael Ibsen, a direct descendant of the king’s sister.

It wasn’t the first time ancient remains had been identified using DNA. If it’s stored in a cold, dry, dark place, DNA can last for thousands of years.

In 2009, a DNA analysis of some bone fragments showed two of Czar Nicholas II’s children were killed along with the rest of the family during the Russian Revolution, despite speculation they could have escaped.

Scientists have even extracted DNA from Neanderthals, who went extinct about 30,000 years ago, in hopes of gaining insight into the evolution of humans.

Distinguish your mutt

“Where does Buddy get his curly tail from? Why does he love digging holes in the backyard? Could I be doing more to make him happier and healthier? Your dog may not be able to tell you the answers — but his DNA can,” claims one dog DNA site.

You’ll probably never figure out why Buddy loves to eat your favorite Italian pumps but you can figure out where he comes from. The website will test your mutt’s DNA against that of more than 190 breeds to determine his genetic background.

“But why?” cat lovers may be asking. “When you understand your dog’s natural tendencies, you can tailor a training, exercise and nutrition program to his needs,” the site explains.

Predict the future

Using blood from the mother and saliva from the father, scientists can now determine whether a fetus has any chromosomal abnormalities that could cause a genetic disorder.

For example, DNA testing can reveal if an unborn baby will have trisomy 21, or Down syndrome.

Researchers are beginning to expand the field of prenatal genetic testing even further, using it to identify potential developmental delays and intellectual disabilities such as autism.

Genetic testing can also reveal risk factors you may have inherited from your parents, such as a high risk for breast or colon cancer.

While this genetic risk factor does not guarantee you will get the disease, it does increase your chances; knowing about the risk may help you take preventive steps.

Help you lose weight

A growing body of research suggests that our ability to lose weight — or gain 10 pounds by simply looking at a piece of chocolate — is shaped in large part by our genes.

Scientists have identified several gene variants that may predispose us, and our children, to obesity. Rodent studies have also shown that up to 80% of body fat is regulated by our genes, according to TIME.

That said, we wouldn’t search for a customized DNA Diet just yet. While there is a genetic component to obesity, our understanding of it is limited, says CNN diet and fitness expert Dr. Melina Jampolis.

Researchers are still trying to figure out how genetics, nutrition and exercise are related so we can help people lose weight and keep it off.

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We have 100 Years To Colonize Another Planet According To Stephen Hawking

stephen-hawking

Mankind needs to colonize another planet in the next 100 years or face extinction, world-renowned physicist Stephen Hawking has warned.

A new BBC documentary called “Stephen Hawking: Expedition New Earth” will show Hawking presenting “his predictions that the human race only has 100 years before we need to colonize another planet,” a news release said.




Hawking, 75, attributes our planet’s imperilment to a variety of forces, including “climate change, overdue asteroid strikes, epidemics and population growth,” the release said, calling Earth an “increasingly precarious” place to live.

Hawking previously estimated that humanity had around 1,000 years left before it would become extinct.

“Although the chance of disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or ten thousand years,” Hawking said in a BBC interview.

space

“By that time we should have spread out into space, and to other stars, so a disaster on Earth would not mean the end of the human race,” he said.

“However, we will not establish self-sustaining colonies in space for at least the next hundred years, so we have to be very careful in this period.”

space

He said advances in science and technology will create “new ways things can go wrong.”

In the documentary series Hawking enlists science and engineering experts, who travel the world to figure out if and how humans can move to other planets.

“Science fact is closer to science fiction than we ever thought,” the release said.

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Chimpanzees Aren’t Super Strong But Their Muscles Are More Powerful Than A Human’s

Since the 1920’s, some researchers and studies have suggested that chimps are ‘super strong’ compared to humans. These past studies implied that chimps’ muscle fibers, the cells that make up muscles are superior to humans’.

But a new study has found that contrary to this belief, a chimp muscles’ power output is just about 1.35 times higher than human muscle of similar size.

A difference the researchers call ‘modest‘ compared with historical, popular accounts of chimp ‘super strength’ being many times stronger than humans.




chimp

If the long-standing, assumption about chimpanzee’s exceptional strength was true, it ‘would indicate a significant and previously unappreciated evolutionary shift in the force and/or power-producing capabilities of skeletal muscle’ in either chimps or humans, whose lines diverged about 7 or 8 million years ago.

The authors of the study concluded that, contrary to some long-standing hypotheses, evolution has not altered the basic force, velocity or power-producing capabilities of skeletal muscle cells to induce the marked differences between chimpanzees and humans in walking, running, climbing and throwing capabilities.

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