"Our study shows how museums still play an
important role in preserving specimens of primary scientific value,"
said study co-author Andrea Cau.
By Brooks Hays
| Feb. 29, 2016 at 10:32 AM
A rendering offers an idea of how large abelisaurs were. Photo by ICL
LONDON, Feb. 29 (UPI) -- After
re-examining a fossilized femur bone belonging to an abelisaur specimen,
researchers can say with more certainty how large these fearsome
predators could become.
Based on their analysis, researchers at Imperial College London
believe the femur belonged to an abelisaur weighing nearly two metric
tons and stretching nine meters, or almost 30 feet. Those dimensions
make it one of the largest abelisaurs ever found.
The new research was detailed in the journal PeerJ.
"Smaller abelisaur fossils have been previously found by
paleontologists, but this find shows how truly huge these flesh eating
predators had become," researcher Alessandro Chiarenza, study co-auhtor,
said in a press release.
"Their appearance may have looked a bit odd as they were probably
covered in feathers with tiny, useless forelimbs, but make no mistake
they were fearsome killers in their time."
Abelisauridae dinosaurs made up for their tiny forelimbs and odd
appearance with massive hindquarters and deadly sharp teeth. They
thrived in what is now northern Africa some 95 million years ago, though
abelisaur fossils have been dated as far back as 170 million years ago
and as recently as 66 million years ago.
The femur was originally found in a Moroccan deposit known as Kem Kem
Beds -- famous for its abundance of predatory dino bones. The site has
confounded researchers who believe it would have been impossible for so
many carnivorous dinosaurs to coexist in such tight quarters.
New analysis suggests the sometimes violent geologic conditions that
created Kem Kem Beds may have also mixed up the strata and chronology of
the fossil record.
Other sites suggest abelisaur were inland hunters, somewhat separated
from their closest cousins, who preferred to hunt fish near lakes and
rivers.
"This fossil find, along with the accumulated wealth of previous
studies, is helping to solve the question of whether abelisaurs may have
co-existed with a range of other predators in the same region,"
Chiarenza explained. "Rather than sharing the same environment, which
the jumbled up fossil records may be leading us to believe, we think
these creatures probably lived far away from one another in different
types of environments."
The fossil was not recently unearthed, but had been sitting in a
museum drawer for several decades -- further proof that closeted
collections hide nearly as many secrets as untouched earth.
"While palaeontologists usually venture to remote and inaccessible
locations, like the deserts of Mongolia or the Badlands of Montana,"
added Andrea Cau, study co-author and researcher at the University of
Bologna, "our study shows how museums still play an important role in
preserving specimens of primary scientific value, in which sometimes the
most unexpected surprises can be discovered."
Unless you've been living under a rock for the past three months,
you've probably heard about turmeric. If not, here's a quick rundown:
Turmeric is a plant in the ginger family that's native to southwest
India. Its root can be boiled, ground and baked to produce an
orangish-yellowish powder. This powder, often referred to as ground
turmeric or turmeric powder, has been a staple of Indian and Pakistani
cuisine for thousands of years. Now, many Americans are also embracing
it. So, why are we suddenly obsessed with this ancient spice?
Because it's being labeled across the internet as an incredibly
powerful "superfood." Google "turmeric health benefits" and you'll find
thousands of articles claiming turmeric can do everything under the sun.
If you believe everything you read, turmeric can supposedly:
whiten teeth
reduce wrinkles
relieve pain
thicken hair
treat and prevent multiple forms of cancer
prevent Alzheimer's
increase weight loss
treat depression
improve sleep
pretty much anything else you could ever want
Pretty crazy, right? Well, don't go out and buy drums of turmeric
quite yet. It's not uncommon for the benefits of trendy foods to get
exaggerated, only to fade from the limelight when people realize those
benefits are mostly hot air. That's why STACK dove into the research to
see if turmeric really deserves to be the next big thing in nutrition.
The Secret Ingredient
Before we address the research, let's check out the basic nutritional
profile of ground turmeric. One tablespoon contains 24 calories, .7
grams of fat, 1.4 grams of fiber and .5 grams of protein. In terms of
the major vitamins and minerals, it contains a solid amount of iron but
not much else. So the basic nutritional facts are pretty pedestrian. If
that's the case, why is turmeric getting so much hype?
The answers lies in curcumin, a powerful antioxidant found almost
exclusively in turmeric. Much of the research into turmeric's health
benefits focus on its curcumin content. When it comes to the purported
benefits of turmeric, curcumin is key.
How much curcumin is in ground turmeric?
According to a 2006 study published in the journal Nutrition and Cancer,
pure turmeric powder averages 3.14% curcumin by weight. So if you eat
100 grams of pure turmeric powder, you will consume about 3.14 grams of
curcumin. A tablespoon of turmeric powder measures 17 grams, containing
roughly .57 grams (or 570 mg) of curcumin. That's a solid amount, but
downing tablespoons of ground turmeric powder can be unpleasant—which is
why many people take turmeric in the form of a capsule supplement.
Now that we know about the importance of curcumin, let's check out the research.
Can Turmeric Help Reduce Inflammation?
Inflammation is the body's natural response to injury, infection or
disease. Its purpose is to protect the body and let it heal. But chronic
inflammation can become a health risk. Many common conditions—such as
asthma and arthritis—are classified as "inflammatory," and inflammation
can contribute to more life-threatening diseases like cancer and
cardiovascular disease. So if turmeric could help reduce inflammation,
that would be an awesome benefit. But is it true? RELATED: Three Powerful Health Benefits of Turmeric
The research says yes. Examine,
an independent site that collates scientific research and disseminates
information on supplementation and nutrition, points to five separate
studies regarding curcumin's effects on inflammation before concluding
that "there appears to be a decrease in disease states or conditions
characterized by inflammation associated with curcumin ingestion" and
that curcumin "does not appear to be too discriminatory in which
inflammatory states it benefits."
The average age of the subjects varied widely among the studies, and
curcumin was found to reduce inflammation related to a wide variety of
conditions, including osteoarthritis, diabetic nephropathy and lichen
planus (a skin disease).
Can Turmeric Change Body Composition?
Millions of Americans are overweight. And millions of Americans
desire to change their bodies for the better. So the promise that
turmeric can potentially aid in fat loss is certainly appealing. But
does the research back it up?
Not quite. There currently isn't enough data to support the idea that
turmeric has a significant effect on body composition. A 2009 animal
study found that dietary curcumin could potentially inhibit the spread
of fat tissue, but not enough high-quality research is yet available to
reach a conclusion on this topic.
Can Turmeric Be Used as a Pain Reliever?
One of turmeric's most interesting reported benefits is pain relief.
Instead of popping a Tylenol, you could just down some turmeric. It's
intriguing, sure. But is it true?
It looks likely. There haven't been a ton of studies on turmeric's
role as a pain reliever, but what's available is encouraging. Examine
writes, "there appear to be decreases in pain associated with curcumin
at higher doses (400-500 mg) which extend to post-operative, arthritic
and general pain symptoms. This does seem comparable to 2g of
acetaminophen in potency."
Acetaminophen is the major active ingredient in Tylenol and many generic pain relievers, so that's a pretty impressive result.
Can Turmeric Help Battle or Even Prevent Forms of Cancer?
Perhaps the most intriguing purported benefit of turmeric is its
ability to battle cancer. It sounds too good to be true, but a growing
amount of research suggests that curcumin can help fight this
all-too-common disease.
According to the University of Maryland Medical Center,
"there has been a great deal of research on turmeric's anti-cancer
properties, but results are still very preliminary. Evidence from test
tube and animal studies suggests that curcumin may help prevent or treat
several types of cancers, including prostate, breast, skin, and colon
cancer. Tumeric's preventive effects may relate to its antioxidant
properties, which protect cells from damage. More research is needed."
Yes, more research is needed, but early results are encouraging regarding curcumin's role in battling cancer.
Can Turmeric Help Prevent Heart Disease?
According to the CDC,
one in every four deaths in the United States can be attributed to
heart disease. Could turmeric help curb this massive public health
issue? RELATED:Heart-Healthy Foods for Athletes
It's too early to tell. Some animal studies have found that curcumin
could help improve your cholesterol profile and thus reduce your risk of
blocked arteries (which lead to heart attacks and stroke), but the same
results have not yet been achieved in human studies. Turmeric could
potentially help prevent heart disease, or it could have no discernible
effect—we'll just have to wait for more research.
Can Turmeric Help Treat Depression?
According to the Anxiety Disorders Association of America,
depression affects nearly 15 million Americans in any given year. Could
turmeric help boost the mood of those suffering with depression?
Research has been sparse but encouraging. One study found that taking
500 mg of curcumin twice a day (roughly equivalent to two tablespoons
of pure powdered turmeric) helped depressed subjects reduce their
symptoms as well as Fluoxetine, a popular anti-depressant medication
frequently marketed under the name "Prozac." However, no placebo group
was used for comparison in the study.
Can Turmeric Make Me More Attractive?
Turmeric's supposed benefits also include beautification: whiter
teeth, clearer skin and thicker hair. They all sound great, but the only
one supported by research is clearer skin. RELATED: Just a Spoonful a Day of These 5 Foods Can Boost Your Health
Several studies have found that ground turmeric helps protect the
skin from UV rays, reduce the appearance of dark spots, reduce acne,
prevent wrinkles and help heal wounds. So the idea that turmeric can
help improve the health and appearance of your skin certainly sounds
valid.
However, claims like whiter teeth and thicker hair aren't backed by
the same amount of research. It's possible that turmeric (more
specifically, curcumin) could help confer those benefits, but the
research is extremely limited at this point in time.
The Verdict
It's not unusual for the benefits of hip, trendy foods to get totally
overblown. However, in the case of turmeric, a solid amount of research
backs up many of its purported health benefits. More research is needed
before concrete conclusions are reached, but even in areas where the
research has been sparse—such as pain relief—early results have been
encouraging. You shouldn't toss out the contents of your medicine
cabinet in favor of turmeric, but it really does seem likely to have
impressive capabilities.
There has yet to be a consensus on the best way to ingest turmeric and/or curcumin. The human body has been found capable of consuming 8 grams of curcumin a day without adverse affects,
so overdosing shouldn't be a major concern. Whether you take it as a
supplement or use it to spice up your food, you should strive to combine
turmeric with a source of fat and/or black pepper. These greatly
increase the absorption rate of curcumin, and many turmeric or curcumin
supplements contain them.
Brandon Hall
- Brandon Hall is an Assistant Content Director for STACK. He
graduated from Lafayette College, where he played football and graduated
with a Bachelor's degree in English.
An analysis of the genome of a Siberian Neanderthal, published today in Nature,
reveals for the first time that humans contributed DNA to the
Neanderthal genome about 100,000 years ago; that's 50,000 years earlierthan the previous estimate. The finding points to an earlier departure from Africa for our human ancestors.
Between 1 and 7 percent of the Siberian Neanderthal’s genome was human—
inherited from people who migrated out of Africa. That suggests humans
and Neanderthals interbred several times. But it also alters our
understanding of human history. Since Neanderthals didn’t make it to
Africa, humans must have left about 50,000 years earlier than
evolutionary biologists had previously estimated. And that's big news,
says Sergi Castellano,an evolutionary biologist at the Max
Planck Institute for Evolutionary Anthropology in Germany and a
co-author of the study. This is "thefirst piece of genetic evidence" that some modern humans "were already out of Africa" 100,000 years ago, he says.
Humans left their mark on Neanderthals, too
Previous genetic analyses have revealed that humans interbred with Neanderthals less than 65,000 years ago, outside of Africa. As a result, Europeans and Asians inherited between 1 and 4 percent of
their DNA from Neanderthals. And that DNA still has an effect on humans
today; just last week scientists linked Neanderthal DNA to a wide range of human health conditions, including depression and nicotine addiction.
But until now, what researchers knew about Neanderthal-human
interactions came from studying the flow of genes from Neanderthals to
humans — and not the other way around. That's mostly because researchers
didn't have the kinds of technologies or the appropriate Neanderthal
DNA samples that would allow them to search in the opposite direction.
This is the first time that scientists have been able to find evidence
that humans left their genetic mark on Neanderthals as well, says
Laurent Frantz, an evolutionary biologist at the University of Oxford
who didn't work on the study. A Siberian Neanderthal with human DNA
To arrive at these conclusions, Castellano and his team searched the
complete genome of a Neanderthal discovered in a Siberian Cave in 2010.
They found that certain regions of the Neanderthal's genome was closely
related to those found in African human populations today. To estimate
the timing of the interbreeding event, the researchers performed a
statistical analyses based on the size and the clustering of the DNA
fragments. This technique works because researchers know that when
animals reproduce, their genetic material mixes with that of other
animals; this causes individual DNA fragments belonging to one
individual to break into smaller pieces as they're passed down through
generations. In this particular case, the technique revealed that the
Siberian Neanderthal's ancestors interbred with humans some 100,000
years ago. Neanderthal toe bone (Bence Viola)
The researchers verified their findings by looking at the genome of a
Denisovan — a member of an extinct human species that split off from
Neanderthals some 380,000 years ago, after Neanderthals became a
subspecies distinct from modern humans. Because Denisovans are more
closely related to Neanderthals than they are to humans, their genomes
can help scientists figure out the kinds of genetic mutations that are
typical of these human subspecies. The analysis showed no evidence of
the human DNA fragments in the Denisovan's genome, which suggests that
these genetic elements were introduced in the Siberian Neanderthal's
genome after Denisovans and Neanderthals evolved away from each other.
Castellano and his team also compared genetic material on chromosome
21 for the Siberia Neanderthal and two different populations of European
Neanderthals. The scientists found no evidence of human integration in
the European samples, which means that ancestors of the introduction of
human DNA into the Siberia Neanderthal probably happened after the
Siberian population branched off from the European Neanderthals, around
110,00 years ago. "This is a big milestone."
The study "doesn't change what we knew before; it's building on it,"
Frantz says. Instead, it gives scientists a better understanding of how
many times human and Neanderthals met. "This is a big milestone," he
says.
Sarah Tishkoff, an evolutionary biologist at University of
Pennsylvania who didn't work on this study, agrees. "This is really
exciting work because it changes what we thought about human
evolutionary history."Butshe also says that the the
comparison of chromosome 21 means that researchers could be missing
signs of human DNA integration in the rest of the European genomes. In
addition, the study doesn't actually reveal much about the interbreeding
event itself. Even though the Neanderthal in the study was found in
Siberia, the human-neanderthal interactions probably occurred further
south, Tishkoff says. But where exactly those interactions happened is a
mystery. The fate of these adventurous humans is also unclear, Frantz
says. "The population is probably partly extinct, and partly integrated
in many different populations across the world."
The study raises a ton of questions, but for now the findings suggest
that what we thought we knew about humans and Neanderthals is just one
tiny piece of the puzzle. "There could have been multiple [human]
migrations coming out of Africa, and some groups just didn't make it,"
Tishkoff says. Research like this helps "paint a picture of what the
ancestry was, not just of modern humans, but of Neanderthals; and that
picture was more complex than we thought."
DNA was taken from ancient human bones, like this skull, from the Dolnte Vestonice burial site in the Czech Republic
L. Lang
Europe went through a major population upheaval about 14,500 years
ago, at the end of the last ice age, according to DNA from the bones of
hunter-gatherers. Ancient DNA studiespublished
in the last five years have transformed what we know about the early
peopling of Europe. The picture they paint is one in which successive
waves of immigration wash over the continent, bringing in new people,
new genes and new technologies.
These studies helped confirm that Europe’s early hunter-gatherers –
who arrived about 40,000 years ago – were largely replaced by farmers
arriving from the Middle East about 8000 years ago. These farmers then
saw an influx of pastoralists from the Eurasian steppe about 4500 years
ago, meaning modern Europe was shaped by three major population turnover events.
Waves of immigration
The latest study suggests things were even more complicated. About 14,500 years ago, when Europe was emerging from the last ice age,
the hunter-gatherers who had endured the chilly conditions were largely
replaced by a different population of hunter-gatherers.
Exactly where this new population came from is still unclear, but it
seems likely that they came from warmer areas further south. “The main
hypothesis would be glacial refugia in south-eastern Europe,” says Johannes Krauseat the Max Planck Institute for the Science of Human History in Jena, Germany, who led the analysis.
As conditions improved, it was these southern hunter-gatherers who
took advantage and migrated into central and northern Europe, he says –
meaning there was a genetic discontinuity with the hunter-gatherer
populations that had lived there earlier.
Martin Frouz
His team analysed mitochondrial DNA extracted from 55 ancient
Europeans, the oldest of whom lived 35,000 years ago – during the
Pleistocene – and the youngest just 7000 years ago, during the Holocene.
Previous studies focused largely on the Holocene, looking at human
remains from the last 10,000 years.
“This is the first glimpse at Pleistocene population dynamics in
Europe,” says Krause. “Little has been done on this older material,
mostly due to lower abundance of material and lesser preservation due to
age.”
“The population turnover after 14,500 years ago was completely unexpected,” says Iosif Lazaridisat
the Harvard Medical School in Boston. “It seems that the
hunter-gatherers of Europe braved the worst of the ice age during the
last glacial maximum but were then replaced when the ice age had begun
to subside.”
Europe’s unusual history
The picture is not yet clear, however, as the study only looked at
mitochondrial DNA sequences, rather than the longer nuclear DNA of other
studies. “Mitochondrial DNA tells only part of the story of a
population,” says Lazaridis. It is important to try to extract nuclear
sequences from the Pleistocene-aged skeletons to find out more about
this earlier population turnover, he says.
The work also may solve a long-standing mystery of why a certain
genetic signature is missing in people of European ancestry. All people
today are members of one of a relatively small number of distinct groups
based on their mitochondrial DNA, which is passed down the maternal
line. The distribution of people in each group gives us a sense of how humans spread across the world in prehistory.
It always seemed that Europe had a very unusual history of
colonisation because one major haplogroup – the M clade – is almost
entirely missing, despite being very common across Asia and even found in Native Americans. Instead, another major haplogroup – the N clade – is most common.
“Some authors had argued that the M and N haplogroups represented two different dispersal events from Africa,” says Toomas Kivisild at the University of Cambridge.
But Krause and his colleagues found that the M clade might actually
have been common in Europe before the population turnover 14,500 years
ago: three of the 18 most ancient humans they studied belonged to the M
clade.
This suggests that the initial colonisation of Europe and Asia may
have involved the same ancient population – and that the M group was
actually lost in Europe much later, perhaps connected in some way to the
mystery upheavals 14,500 years ago.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2016.01.037 Read more:The three ancestral tribes that founded Western civilisation
Europe wasn't a very hospitable place fifteen millennia ago. The
westernmost landmass of the Eurasian continent had endured a long ice
age, with glaciers stretching across northern Europe and into the region
we now call Germany. But suddenly, about 14,500 years ago, things
started to warm up quickly. The glaciers melted so fast around the globe
that they caused sea levels to rise 52 feet in just 500 years.
Meanwhile, the environment was in chaos, with wildlife trying vainly to
adjust to the rapid fluctuations in temperature. Humans weren't immune
to the changes, either.
A new, comprehensive analysis of ancient European DNA published today in Current Biology magazine
by an international group of researchers reveals that this period also
witnessed a dramatic shift in the human populations of Europe.
Bloodlines of hunter-gatherers that had flourished for thousands of
years disappeared, replaced with a new group of hunter-gatherers of
unknown origin.
Researchers discovered this catastrophic population meltdown by
sequencing the mitochondrial DNA of 35 people who lived throughout
Europe between 35 and 7 thousand years ago. Mitochondrial DNA is a tiny
amount of genetic material that's inherited virtually unchanged via the
maternal line, and thus it serves as a good proxy for relatedness over
time. Two people from the same maternal stock share almost the same
mitochondrial DNA, even if separated by thousands of years, because this
kind of DNA evolves very slowly.
It's long been known that two such related groups, called M clade and
N clade, poured out of Africa and across the Eurasian continent about
55 thousand years ago. Some of these people wandered so far that they
even made it to Australia, eventually. And yet something rather odd
happened to the people of Europe. Only members of the N clade survived
into the present day, while Asia, Australia, and the Americas are full
of the offspring of both N and M. Until the new study in Current Biology,
scientists believed that the most likely explanation was that roughly
45 thousand years ago, Europe was colonized solely by the N clade, while
both clades settled elsewhere around the world.
But thanks to sequencing the mitochondrial DNA in those 35 ancient
people, the researchers uncovered something previously unknown. There
were, in fact, people from the M clade alive in Europe as recently as 25
thousand years ago. But something happened to wipe them out during the
cold, dry glacial maximum that gripped the world between 25 and 14.5
thousand years ago.
Enlarge/
In this image, you can see the clades of the people
who the team
sequenced, and how they fared over time. The
R and U clades are all
descended from the N clade. Note that
M is present until 25 thousand
years ago, when the ice age begins.
Current Biology
There are obvious reasons why Europeans might have suffered a
population bottleneck during the ice age, or the Last Glacial Maximum.
Food was scarce, and once-fecund habitats became unlivable. Groups that
once roamed the wide-open fields of Europe retreated into small refuges,
separated by walls of ice or frozen drought wastelends created when
glaciation locks up atmospheric water. The researchers believe that the M
clade, whose members were found far to the north, may have slowly died
out during that period. After the glaciers retreated, the survivors
were replaced by a new N-related population from elsewhere on the
continent.
Write the researchers:
The potential impact of climatic events on the
demography, and thus the genetic diversity of early Europeans, has
previously been difficult to quantify, but it likely had consequences
for the relative components of ancient ancestry in modern-day
populations. Our demographic modeling reveals a dynamic history of
hunter-gatherers, including a previously unknown major population shift
during the Late Glacial interstadial (the BøllingAllerød, 14.5 ka).
Under our best-fitting model, the small initial founder population of
Europe slowly grows up until 25 ka and survives with smaller size in LGM
[Last Glacial Maximum] climatic refugia (25–19.5 ka) before
re-expanding as the ice sheets retract. Although this model supports
population continuity from pre- to post-LGM, the genetic bottleneck is
consistent with the apparent loss of hg M in the post-LGM. Globally, the
early warming phases of the Late Glacial are strongly associated with
substantial demographic changes, including extinctions of several
megafaunal species and the first expansion of modern humans into the
Americas. In European hunter-gatherers, our model best explains this
period of upheaval as a replacement of the post-LGM maternal population
by one from another source.
Essentially, an entire genetic line in Europe was wiped out by
climate change. You might say that today's European population still
bears the scars of an ancient ice age in its mitochondrial DNA. Current Biology, 2016. DOI: 10.1016/j.cub.2016.01.037.
Why Did Ancient Europeans Just Disappear 14,500 Years Ago?
By Tia Ghose
March 2, 2016 11:22 AM
The skull of a man who lived between 36,200
and 38,700 years ago in Kostenki in western Russia.
Some of Europe's earliest inhabitants mysteriously vanished
toward the end of the last ice age and were largely replaced by others, a
new genetic analysis finds.
The finds come from an analysis of dozens of ancient fossil remains collected across Europe.
The genetic turnover was likely the result of a rapidly changing
climate, which the earlier inhabitants of Europe couldn't adapt to
quickly enough, said the study's co-author, Cosimo Posth, an
archaeogenetics doctoral candidate at the University of Tübingen in
Germany.
[Top 10 Mysteries of the First Humans]
The temperature change around that time was "enormous compared to the
climactic changes that are happening in our century," Posth told Live
Science. "You have to imagine that also the environment changed pretty
drastically." A twisted family tree
Europe has a long and tangled genetic legacy. Genetic studies have revealed that the first modern humans who poured out of Africa, somewhere between 40,000 and 70,000 years ago, soon got busy mating with local Neanderthals. At the beginning of the agricultural revolution, between 10,000 and 12,000 years ago, farmers from the Middle East
swept across Europe, gradually replacing the native hunter-gatherers.
Around 5,000 years ago, nomadic horsemen called the Yamnaya emerged from
the steppes of Ukraine and intermingled with the native population. In
addition, another lost group of ancient Europeans mysteriously vanished about 4,500 years ago, a 2013 study in the journal Nature Communications found.
But relatively little was known about human occupation of Europe between the first out-of-Africa event and the end of the last ice age,
around 11,000 years ago. During some of that time, the vast Weichselian
Ice Sheet covered much of northern Europe, while glaciers in the
Pyrenees and the Alps blocked east-west passage across the continent. Lost lineages
To get a better picture of Europe's genetic legacy during this cold
snap, Posth and his colleagues analyzed mitochondrial DNA — genetic
material passed on from mother to daughter — from the remains of 55
different human fossils between 35,000 and 7,000 years old, coming from
across the continent, from Spain to Russia. Based on mutations, or
changes in this mitochondrial DNA, geneticists have identified large
genetic populations, or super-haplogroups, that share distant common
ancestors.
"Basically all modern humans outside of Africa, from
Europe to the tip of South America, they belong to these two
super-haplogroups that are M or N," Posth said. Nowadays, everyone of
European descent has the N mitochondrial haplotype, while the M subtype
is common throughout Asia and Australasia.
The team found that in
ancient people, the M haplogroup predominated until about 14,500 years
ago, when it mysteriously and suddenly vanished. The M haplotype carried
by the ancient Europeans, which no longer exists in Europe today,
shared a common ancestor with modern-day M-haplotype carriers around
50,000 years ago.
The genetic analysis also revealed that
Europeans, Asians and Australasians may descend from a group of humans
who emerged from Africa and rapidly dispersed throughout the continent
no earlier than 55,000 years ago, the researchers reported Feb. 4 in the
journal Current Biology. Time of upheaval
The team suspects this upheaval may have been caused by wild climate swings.
At the peak of the ice age, around 19,000 to 22,000 years ago, people
hunkered down in climactic "refugia," or ice-free regions of Europe,
such as modern-day Spain, the Balkans and southern Italy, Posth said.
While holdouts survived in a few places farther north, their populations
shrank dramatically.
Then around 14,500 years ago, the
temperature spiked significantly, the tundra gave way to forest and many
iconic beasts, such as woolly mammoths and saber-toothed tigers, disappeared from Eurasia, he said.
For whatever reason, the already small populations belonging to the M
haplogroup were not able to survive these changes in their habitat, and a
new population, carrying the N subtype, replaced the M-group ice-age
holdout, the researchers speculate.
Exactly where these replacements came from is still a mystery. But one
possibility is that the newer generation of Europeans hailed from
southern European refugia that were connected to the rest of Europe once
the ice receded, Posth speculated. Emigrants from southern Europe would
also have been better adapted to the warming conditions in central
Europe, he added.
A
photo of the modern owl butterfly (Caligo Memnon) below a fossilized
Kalligrammatid lacewing (Oregramma illecebrosa) shows some remarkable
similarities. (James Di Loreto/Smithsonian)
Before
butterflies, there were Kalligrammatid lacewings — winged insects that
took butterfly-like form at least 40 million years before the modern
bugs first came on the scene. But the remarkably butterflyesque species Oregramma illecebrosa, described in a study published Wednesday in Proceedings of the Royal Society B, isn't a butterfly ancestor:
Other members of its lineage went on to become entirely different sorts
of insects. Instead, this striking similarity is a case of convergent
evolution — the same shapes, patterns and perhaps even behaviors came
about twice, totally independently.
The findings come thanks to
some especially well-preserved fossils found in northeastern China,
which allowed researchers to study the ancient insects more closely than
ever before.
"They've been known for about 100 years, but in the
1960s there were some specimens that made people say, gosh, these
really look like butterflies," Smithsonian paleoecologist Conrad Labandeira,
lead author on the study, told The Washington Post. "But we knew they
were unrelated. That's where it stood for some 55 years."
But once Labandeira and his team — an international collaboration of scientists —
got a hold of the Chinese fossils, things got much more interesting.
The resemblance is so strong that even experts were fooled at a
distance: Labandeira recalls a colleague from the entomology department
assuming the fossil on the table was a butterfly from 20 feet away.
"When I told him to come closer, and he looked again, his jaw dropped," Labandeira said.
One of the more remarkable similarities is superficial in nature: The spots seen on the Oregramma illecebrosa fossils are nearly identical to patterns found on owl butterflies today.
These so-called eye spots mimic the peepers of a large bird, scaring
off predators that might otherwise make a quick snack of a delicate
butterfly.
It's thought that Oregramma illecebrosa last
shared a common ancestor with modern butterflies more than 320 million
years ago. The fact that two quite unrelated insects developed these
markings millions of years apart from one another is a perfect example
of convergent evolution: Oregramma illecebrosa might
not have shared space with owls, but plenty of big-eyed creatures
— perhaps even dinosaurs, the prominent predators of the Jurassic period
— could have served as inspiration for the markings. An Oregramma illecebrosa would
have had a better chance of surviving dino dinnertime if it could pass
itself off as a bigger animal, and over time — as faux-eyed insects
continued to breed more successfully than those without the markings
— the patterns would become more complex.
Then, millions of years
later, an unrelated group of insects did the exact same thing. What
worked well in the Jurassic still works well today.
But there are
signs that these ancient bugs shared behavioral traits with modern
butterflies, too: They had modified hairs on their legs for collecting
pollen, just as modern butterflies do. And they even had long
proboscises, which modern butterflies use to suck nectar from flowers
— even though flowering plants didn't exist at the time. Instead, Oregramma illecebrosa and its ilk would have gathered dry and liquid pollen from primitive, non-flowering plants.
This
is another case of convergent evolution, Labandeira explained. Other
studies have found that multiple groups of insects had these long
mouth-parts before flowers existed, so they must have evolved
specifically to suck the liquids of plants that have long gone extinct.
Then, when flowers became ecologically dominant, the whole system was
reinvented.
"It’s kind of like a baseball team," Labandeira said.
"The positions are the same, but the players are changed. It was a
different world that these insects were evolving in. So they’re serving
very similar roles, but they’re completely different."
Nicknamed the "buzzsaw shark," this 270 million-year-old creature is actually an extinct relative of the ratfish called a Helicoprion. Its bizarre tooth arrangement has confused scientists for over a century, but one artist finally got it right.
Ray Troll, whose art show about Hilicoprion has been touring
the US for the past three years, has been on the front lines of
scientific research about one of the strangest fossils ever found. When
geologist Alexander Petrovich Karpinsky discovered
the creature's tooth whorl in 1899, at first he thought it was a kind
of ammonite because the teeth looked so much like the ammonite's spiral
shell. Paleo expert Brian Switek writes that it took Karpinsky a little while
to realize that it was actually part of a larger animal. Over the next
century, many different paleontologists offered explanations for what it
might be, including a defensive formation on Helicoprion's nose, a ridge on its back, or even sticking out of its mouth like a spiky, curled tongue.
Enlarge/ All the different ways that scientists have tried to
explain where Helicoprion's spiral teeth were positioned.
Over at the Smithsonian,
there's a great profile of Troll, who has done
a lot more than make art
of this crazy fish. He's actually added to the
scholarship on it:
Troll’s passion, however, has served a purpose far beyond
the aesthetic charm of a framed picture—it has shaped the scientific
community’s knowledge of Helicoprion itself. Back in the
mid-1990s, when he wrote and spoke with [paleontologist Svend Erik
Bendix] Almgreen, Troll discovered that the scientist had published his
hypothesis about the buzz shark’s physiology in an obscure paper in
1966. This knowledge remained hidden, lost to memory even to prominent
paleontologists, until 2010, when an undergraduate student working as an
intern at the Idaho Museum of Natural History got in touch with Troll.
As a result, Troll began working with paleontologist Leif Tapanila,
who used used CT scans to image a whole skull of a Helicoprion—revealing
that the buzzsaw shape was actually part of its lower jaw, used for
slicing food and pushing it toward the back of the fish's mouth. It
seems that the teeth formed in the jaw next to the topmost part of the
spiral, then gradually worked their way down and back into the jaw. Once
there, the teeth would be absorbed into cartilage and eventually turned
into teeth again. These scans became the basis for an article published in 2013 in Biology Letters, which also included some of Troll's artwork of the buzzsaw in its rightful place.
Enlarge/ Here you can see the fossils that Tapanila put into the CT scanner, along with the structure they revealed.
Royal Society
Troll's drawings and sculptures, which are still touring the US today (currently they are at the University of Oregon's Museum of Natural and Cultural History),
are a reminder that paleoartists contribute a great deal to scientific
discovery. Taking a whimsical approach, Troll called his show "The Buzz
Sharks of Long Ago." His goofy humor is a perfect way to shine light on
the truth of natural history, which is often so weird that it might as
well be art.
Published:
15:00 EST, 1 February 2016
| Updated:
19:11 EST, 1 February 2016
ns have been blamed for killing off the Neanderthals around 30,000
years ago by breeding with them and even murdering them.
But now experts believe it was our ancestors' artistic and innovative abilities that ultimately led to the Neanderthal's demise.
The
experts believe our more advanced lifestyle gave us a cultural and
competitive edge over our ancient cousins and this paved the way for
their extinction.
+6
Experts believe Neanderthals (model
pictured right) were wiped out by artistic and innovative modern
humans. The study claims our more advanced lifestyle gave us a cultural
and competitive edge over our ancient cousins which ultimately paved the
way for their extinction
Researchers
from Stanford University in California and Meiji University in Japan
used computer models to show a small modern human population was capable
of displacing a larger Neanderthal one, if they had a sufficiently
large cultural advantage - such as artistic capability.
The
Neanderthals faced a vicious circle because as modern humans' cultural
advantages increased, their competitive advantage also increased, which
in turn further boosted their cultural advantage.
The
results, published in the journal Proceeding of the National Academy of
Sciences, add to a growing body of evidence, that modern humans
destroyed the Neanderthals.
HOW ART GAVE OUR ANCESTORS THE EDGE OVER NEANDERTHALS
Research
has shown cultural life became increasingly important for humans with
childhoods becoming longer than those of Neanderthals, for instance.
Neanderthal
children's teeth grew more quickly than modern human children, meaning
they must have had a much reduced opportunity to learn from their
parents and clan members.
Experts
believe our ancestors then moved from a primitive 'live fast and die
young' strategy to a 'live slow and grow old' one - making humans one of
the most successful organisms on Earth.
Elsewhere,
modern humans gained new cultural abilities that allowed them to better
exploit their environments and out-compete groups such as Neanderthals.
Archaeologists
have found cave paintings, rock art and beads dating from after 50,000
years ago, where before then there was limited evidence of art and
culture.
The
study explains art is an indicator of humans' ability to innovate, and
once people start innovating, technology changes rapidly.
It was likely this process that allowed humans to successfully populate the planet.
Professor
Marcus Feldman, of Stanford University in California, said: 'Most
archaeologists argue the advantage to modern humans lay in a higher
culture level, but a sizable minority dispute this view.'
He
continued that competition between the two species may have occurred
when a modern human entered a region occupied by a larger Neanderthal
population.
Professor Feldman said: 'We present a model for this replacement.
'Our
findings shed light on the disappearance of the Neanderthals, showing
that endogenous factors such as relative culture level, rather than such
extrinsic factors as epidemics or climate change, could have caused the
eventual exclusion of a comparatively larger population by an initially
smaller one.'
Research
has shown cultural life became increasingly important for humans with
childhoods becoming longer than those of Neanderthals, for instance.
Neanderthal
children's teeth grew much more quickly than modern human children,
meaning they must have had a much reduced opportunity to learn from
their parents and clan members.
Professor
Feldman believes our ancestors moved from a primitive 'live fast and
die young' strategy to a 'live slow and grow old' one - making humans
one of the most successful organisms on the planet.
This means Neanderthals, who lived in small populations across Europe, were ill-equipped to deal with the newcomers.
+6
The researchers said: 'Our findings
shed light on the disappearance of the Neanderthals, showing that
endogenous factors such as relative culture level, rather than such
extrinsic factors as epidemics...could have caused the eventual
exclusion [of Neanderthals]' A Neanderthal skull is pictured above
+6
Modern humans gained new cultural
abilities (a cave painting from Montignac, France is pictured) that
allowed them to better exploit their environments and out-compete groups
like Neanderthals. The study explained art is an indicator of humans'
ability to innovate, and once people start innovating, technology
changes rapidly
Elsewhere,
modern humans gained new cultural abilities that allowed them to better
exploit their environments and out-compete groups such as Neanderthals.
In
particular, archaeologists have found evidence that big changes
occurred in human society around the time the Neanderthals disappeared.
+6
Researchers believe the artistic and inventive attributes
(illustrated) of modern humans led to us out-competing Neanderthals
These include cave paintings, rock art and beads dating from after 50,000 years ago.
Before then there was limited evidence of art and culture.
The
study explained art is an indicator of humans' ability to innovate, and
once people start innovating, technology changes very rapidly.
It was likely this process that allowed humans to successfully populate the planet.
However,
the study will prove controversial because jewellery thought to have
been made by neanderthals up to 130,000 years ago has previously been
earthed.
Eight
talons taken from a white-tailed eagle found at Neanderthal site in
Krapina in Croatia were used to create a necklace or bracelet.
And
last year, experts claimed weapons used by modern humans were no better
than the Neanderthals' handiwork, signifying our direct ancestors were
not technologically superior.
Dr
Seiji Kadowaki, first author of this earlier study from Nagoya
University, Japan, said: 'We're not so special, I don't think we
survived Neanderthals simply because of technological competence.'
Early modern humans expanded the geographic area they inhabited out of Africa during a period of 55,000 to 40,000 years ago.
The
researchers studied stone tools that were used by people in the Early
Ahmarian culture and the Protoaurignacian culture, living in south and
west Europe and west Asia around 40,000 years ago.
They used small stone points as tips for hunting weapons like throwing spears.
Researchers
previously considered these to be an important innovation - one that
helped the humans migrate from west Asia to Europe, where Neanderthals
were living.
+6
Previously, researchers studied stone
tools that were used by
people in the Early Ahmarian culture and the
Protoaurignacian
culture, living in south and west Europe and west Asia
around
40,000 years ago. They found the human tools (pictured)
were no
more effective than Neanderthal-created tools of the same era
However, the research revealed a timeline that doesn't support this theory.
If the innovation had led to the migration, evidence would show the stone points moving in the same direction as the humans.
But
the study showed the possibility that the stone points appeared in
Europe 3,000 years earlier than in the Levant, a historical area in west
Asia.
'We
looked at the basic timeline revealed by similar stone points, and it
shows that humans were using them in Europe before they appeared in the
Levant - the opposite of what we'd expect if the innovation had led to
the humans' migration from Africa to Europe,' said Dr Kadowaki.
'Our
new findings mean that the research community now needs to reconsider
the assumption that our ancestors moved to Europe and succeeded where
Neanderthals failed because of cultural and technological innovations
brought from Africa or west Asia.'
They believe the timings imply several new scenarios about the migration of modern humans into Europe.
NEANDERTHALS WERE KILLED OFF BY MODERN DISEASES, EXPERTS CLAIM
In
April last year, scientists claimed it may have been infectious
diseases carried by our modern human ancestors as they migrated out of
Africa that finished the Neanderthals off.
Experts
studying genetic, fossil and archaeological evidence said that
Neanderthals suffered from a wide range of diseases that still plague us
today.
They
have found evidence that suggests our prehistoric cousins would have
been infected by diseases such as tuberculosis, typhoid, whooping cough,
encephalitis and the common cold.
But
anthropologists from Cambridge University and Oxford Brookes University
said that new diseases carried by modern humans may have led to the
downfall of Neanderthals.
+6
A previous study said Neanderthals may
have succumbed to infectious diseases carried to Europe by modern
humans as they migrated out of Africa. Bacteria that cause tuberculosis
are shown above
They
speculate that pathogens like Heliocbacter pylori, the bacteria that
causes stomach ulcers, were brought to Europe by modern humans from
Africa and may have infected Neanderthals, who would have been unable to
fight off these new diseases.
However,
Neandethals may have also helped modern humans by passing on slivers of
immunity against some diseases to our ancestors when they interbred.
Dr
Simon Underdown, a principal lecturer in anthropology at Oxford Brookes
University and co-author of the study, said: 'As Neanderthal
populations became more isolated they developed very small gene pools
and this would have impacted their ability to fight off disease.
'When Homo sapiens came out of Africa they brought diseases with them.
'We
know that Neanderthals were actually much more advanced than they have
been given credit for and we even interbred with them.
'Perhaps the only difference was that we were able to cope with these diseases but Neanderthals could not.'
WASHINGTON—Around 50,000 years ago, anatomically modern humans
shacked up with some Neanderthals—and the genetic consequences are still
doing a walk of shame through our generations.
The questionable interbreeding left traces of Neanderthal DNA
that are linked to mood disorders, mostly depression, as well as
tobacco-use disorders, skin conditions, and hypercoagulation (excessive
blood clotting), according to a new study published Thursday in Science.
The findings lend support to the theory that our past hominin hook-up
has had a lasting influence on modern humans’ health. The data also
offers hints at genetic adaptations of our ancient ancestors and,
potentially, new insights into the diseases they help cause in modern
humans, the authors suggest.
Having these traces of Neanderthal DNA doesn’t “doom us” to having
these diseases, cautioned John Capra, bioinformaticist at Vanderbilt
University and coauthor of the study. The genetic traces linked to
disease in modern humans doesn’t mean that Neanderthals were stricken
with those diseases either, he added. In fact, some of them could have
been advantageous.
For instance, excessive blood clotting can result in strokes and
heart attacks in modern humans. However, quick clotting is also a
natural defense against bacteria entering a wound site, Capra explained.
He hypothesizes that some of the Neanderthal traces that linger in
modern humans may have been advantageous at one point. This would make
sense, since the Neanderthals were likely highly adapted to their own
environments, he added. “Perhaps spending a night or two with a
Neanderthal is a relatively small price to pay for getting thousands of
years of adaptations,” Capra said.
Researchers have hypothesized for some time that Neanderthal DNA—the
bits that have been maintained in modern humans’ genomes, that is—can
influence health. After all, Eurasian genomes contain about 1.5 to 4
percent Neanderthal DNA. But proving that the tiny fragments of ancient
DNA has influence has been tricky.
For the study, Capra and colleagues harvested genetic and disease
incidence data from the electronic health records of more than 28,000
adults of European ancestry. Next, the researchers compared the genetic
data with that of Neanderthal genomes, looking for genetic fingerprints
of the ancient hominin’s DNA in modern genomes. Then they looked for
links between the presence of Neanderthal DNA and disease incidence in
the adults. Capra and colleagues found a number of links, some of which
seemed to be associated with sunlight exposure, they speculated. The
researchers found Neanderthal DNA variations associated with skin
conditions, including actinic keratosis, precancerous skin lesions
linked to over exposure to the sun. There were also Neanderthal links to
depression, a mood disorder that can in some cases be linked to sun
exposure in modern humans, the authors point out.
Less clear, however, was the link to tobacco-use disorders, which was
found in the analysis. It’s unlikely that Neanderthals were taking
smoke breaks 50,000 years ago outside their caves, Capra said. But the
genetic hitch in modern humans in their modern environments may confer a
complex neurological trait that now creates a predisposition to
nicotine addiction. Studying the link further could offer new
information on understanding and even treating addiction in humans,
Capra explained.
Moving forward, Capra expects that more research using big genetic
and disease datasets will reveal more ancient fragments of our genome
and their influence on health. After all, he said, human’s family tree
is a lot more bush-like than tree-like. Science, 2015. DOI: 10.1126/science.aad2149 (About DOIs).
![The researchers said: 'Our findings shed light on the disappearance of the Neanderthals, showing that endogenous factors such as relative culture level, rather than such extrinsic factors as epidemics...could have caused the eventual exclusion [of Neanderthals]' A Neanderthal skull is pictured above](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_szZvxt0ivIToMSL0Ir1y3mIovdg9gdX_F_hm5-aa9cdt6E9ybLR3CGnaGGBA_tC6vqLOmEXEVlSVIR8ewfZCp1MqYetALq2p75WbNyBWo8kTXc7devsDwMDUTw9K_6ONysMORiZb-bfcmV_sjQLGVbi5JqVOS-Gh0fLKGt80oP3F6cBLlX3dbWexLEg_Z3QMMe7gAVE9Qxjn3aPwldkBtISeBZIZdd_JObYAtaDI4_vJc8i9amNz0I-Q8tz_oNzvcbvQ=s0-d)
