Man charged for theft of fossil footprints in Crete

Greek police arrested on Friday a 55-year-old man in connection with the theft of 10 fossilised footprints which were stolen on earlier this week from the site where they were uncovered in Kissamos, Western Crete, authorities said.

The vandalised site, showing fresh sand along the edges of the slab where it has been lifted and the holes left 
by the removal of two blocks in the centre [Credit: Babis Fassoulas]

The suspect faces charges of violating laws on protection of cultural heritage. Authorities were able to locate quickly in regions of Kissamos and Thessaloniki all ten fossils. The objects will be send to Chania to be examined by experts.

The site has been buried in haste to avoid further thefts [Credit: Babis Fassoulas]

Ten of some 40 footprints on the site were cut away and removed from the rock where they were found by a Polish paleontologist in 2002. The 5.7-million-year-old fossils are believed to belong to a hominid ancestor of modern humans and their discovery could upend established theories of human evolution.

The buried site [Credit: Babis Fassoulas]

The theft was reported by a member of the public that visited the site on Tuesday and alerted local police, and was later confirmed by the Natural History Museum of Crete. The investigation of the case is continuing.

Source: ANA-MPA [September 15, 2017]

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When ancient fossil DNA isn't available, ancient glycans may help trace human evolution

Ancient DNA recovered from fossils is a valuable tool to study evolution and anthropology. Yet ancient fossil DNA from earlier geological ages has not been found yet in any part of Africa, where it's destroyed by extreme heat and humidity. In a potential first step at overcoming this hurdle, researchers at University of California San Diego School of Medicine and Turkana Basin Institute in Kenya have discovered a new kind of glycan -- a type of sugar chain -- that survives even in a 4 million-year-old animal fossil from Kenya, under conditions where ancient DNA does not.

Partial upper jaw of Australopithecus anamensis, a primitive hominin, recovered from the bone bed 
excavated at the Allia Bay site [Credit: Meave Leakey, PhD]

While ancient fossils from hominins (human ancestors and extinct relatives) are not yet available for glycan analysis, this proof-of-concept study, published in Proceedings of the National Academy of Sciences, may set the stage for unprecedented explorations of human origins and diet.

"In recent decades, many new hominin fossils were discovered and considered to be the ancestors of humans," said Ajit Varki, MD, Distinguished Professor of Medicine and Cellular and Molecular Medicine at UC San Diego School of Medicine. "But it's not possible that all gave rise to modern humans -- it's more likely that there were many human-like species over time, only one from which we descended. This new type of glycan we found may give us a better way to investigate which lineage is ours, as well as answer many other questions about our evolution, and our propensity to consume red meat."

Glycans are complex sugar chains on the surfaces of all cells. They mediate interaction between cells and the environment, and often serve as docking sites for pathogens. For millions of years, the common ancestors of humans and other apes shared a particular glycan known as Neu5Gc. Then, for reasons possibly linked to a malarial parasite that exploited Neu5Gc as a means to establish infection, a mutation that probably occurred between 2 and 3 million years ago inactivated the human gene encoding the enzyme that makes the molecule. The loss of Neu5Gc amounted to a radical molecular makeover of human ancestral cell surfaces and might have created a fertility barrier that expedited the divergence of the lineage leading to humans.

Today, chimpanzees and most other mammals still produce Neu5Gc. In contrast, only trace amounts can be detected in human blood and tissue -- not because we make Neu5Gc, but, according to a previous study by Varki's team, because we accumulate the glycan when eating Neu5Gc rich red meat. Humans mount an immune response to this non-native Neu5Gc, possibly aggravating diseases such as cancer.

In their latest study, Varki and team found that, as part of its natural breakdown, a signature part of Neu5Gc is also incorporated into chondroitin sulfate (CS), an abundant component in bone. They detected this newly discovered molecule, called Gc-CS, in a variety of mammalian samples, including easily detectable amounts in chimpanzee bones and mouse tissues.

Like Neu5Gc, they found that human cells and serum have only trace amounts of Gc-CS -- again, likely from red meat consumption. The researchers backed up that assumption with the finding that mice engineered to lack Neu5Gc and Gc-Cs (similar to humans) had detectable Gc-CS only when fed Neu5Gc-containing chow.

Excavation of the bone bed at the Allia Bay site, East Turkana, in 1996. A cross section of the bone bed 
can be seen passing diagonally from the center of the image to the right hand corner. This is the site 
where researchers collected a 4-million-year-old bovid fossil that contained Gc-CS 
[Credit: Meave Leakey, PhD]

Curious to see how stable and long-lasting Gc-CS might be, Varki bought a relatively inexpensive 50,000-year-old cave bear fossil at a public fossil show and took it back to the lab. Despite its age, the fossil indeed contained Gc-CS.

That's when Varki turned to a long-time collaborator -- paleoanthropologist and famed fossil hunter Meave Leakey, PhD, of Turkana Basin Institute of Kenya and Stony Brook University. Knowing that researchers need to make a very strong case before they are given precious ancient hominin fossil samples, even for DNA analysis, Leakey recommended that the researchers first prove their method by detecting Gc-CS in even older animal fossils. To that end, with the permission of the National Museums of Kenya, she gave them a fragment of a 4-million-year-old fossil from a buffalo-like animal recovered in the excavation of a bone bed at Allia Bay, in the Turkana Basin of northern Kenya. Hominin fossils were also recovered from the same horizon in this bone bed.

Varki and team were still able to recover Gc-CS in these much older fossils. If they eventually find Gc-Cs in ancient hominin fossils as well, the researchers say it could open up all kinds of interesting possibilities.

"Once we've refined our technique to the point that we need smaller sample amounts and are able to obtain ancient hominin fossils from Africa, we may eventually be able to classify them into two groups -- those that have Gc-CS and those that do not. Those that lack the molecule would mostly likely belong to the lineage that led to modern humans," said Varki, who is also adjunct professor at the Salk Institute for Biological Studies and co-director of the UC San Diego/Salk Center for Academic Research and Training in Anthropogeny (CARTA).

In a parallel line of inquiry, Varki hopes Gc-CS detection will also reveal the point in evolution when humans began consuming large amounts of red meat.

"It's possible we'll one day find three groups of hominin fossils -- those with Gc-CS before the human lineage branched off, those without Gc-CS in our direct lineage, and then more recent fossils in which trace amounts of Gc-CS began to reappear when our ancestors began eating red meat," Varki said. "Or maybe our ancestors lost Gc-CS more gradually, or only after we began eating red meat. It will be interesting to see, and we can begin asking these questions now that we know we can reliably find Gc-CS in ancient fossils in Africa."

Leakey is also hopeful about the role Gc-CS could play in the future, as an alternative to current approaches.

"Because DNA rapidly degrades in the tropics, genetic studies are not possible in fossils of human ancestors older than only a few thousand years," she said. "Therefore such ancient glycan studies have the potential to provide a new and important method for the investigation of human origins."

Author: Heather Buschman | Source: University of California - San Diego [September 11, 2017]

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First primates were built for leaping, fossil ankle suggests

A 52-million-year-old ankle fossil suggests our prehuman ancestors were high-flying acrobats. These first primates spent most of their time in the trees rather than on the ground, but just how nimble they were as they moved around in the treetops has been a topic of dispute.

This tiny ankle bone belonged to one of the earliest members of the primate family tree. The 52-million-year-old fossil 
suggests that the first primates were expert leapers. Discovered more than 30 years ago by paleontologist 
Marc Godinot, the fossil is now housed at the Muséum National d'Histoire Naturelle in Paris 
[Credit: Douglas Boyer, Duke University]

For years, scientists thought the ancestors of today's humans, monkeys, lemurs and apes were relatively slow and deliberate animals, using their grasping hands and feet to creep along small twigs and branches to stalk insects or find flowers and fruits.

But a fossil study published in the Journal of Human Evolution suggests the first primates were masters at leaping through the trees.

Paleontologists working in a quarry in southeastern France uncovered the quarter-inch-long bone, the lower part of the ankle joint.

The fossil matched up best with a chipmunk-sized creature called Donrussellia provincialis.

Previously only known from jaws and teeth, Donrussellia is thought be one of the earliest members of the primate family tree, on the branch leading to lemurs, lorises and bush babies.

Duke University assistant professor Doug Boyer and colleagues studied scans of Donrussellia's ankle and compared it to other animals, using computer algorithms to analyze the 3-D digital shape of each tiny bone.

They were surprised to find that Donrussellia's ankle was not like those of other primates, but was more similar to those of treeshrews and other nonprimate species.

The team's analyses also suggest the animal didn't just clamber or scurry along small branches. Instead, it may have been able to bound between trunks and branches, using its grasping feet to stick the landing.

The researchers say that -- contrary to what many scientists thought -- the first primates may have evolved their acrobatic leaping skills first, while anatomical changes that allowed them to cling to slender branch tips and creep from tree to tree came later.

"Being able to jump from one tree to another might have been important, especially if there were ground predators around waiting to snag them," Boyer said.

Author: Robin Ann Smith | Source: Duke University [September 11, 2017]

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Monkey tool use threatens prey numbers, say researchers

Using tools to search for food is affecting primate prey numbers and could potentially lead to prey species extinction, new Oxford research suggests.

Using tools to search for food is affecting primate prey numbers and could potentially lead to prey species extinction, 
new Oxford research suggests [Credit: Amanda Tan]

Once thought to be a skill unique to humans, recent studies have shown that some animals, such as monkeys, apes, birds and otters, are able to use tools to find food that would otherwise be inaccessible to them.

Tool use has been a gift and a curse for human society, on the one hand allowing people to progress to become one of the most successful species on the planet, but on the other endangering and pushing many prey species to the brink of extinction, particularly in the case of ocean overfishing.

In new research published in the journal eLife and funded by the European Research Council, scientists from the Department of Anthropology and Archaeology at Oxford University have assessed whether tool use can negatively affect prey species in the same way it does in human society. Using the primate species macaques (Macaca fascicularis) as an example, the findings reveal that these monkeys not only use tools but experience the same adverse effects, such as prey decline, which could eventually lead to a loss of tool skills. The paper was presented today at the British Science Festival.

Led by Dr Lydia Luncz, a postdoctoral researcher at Oxford, the team used archaeological evidence to demonstrate that the macaques' use of tools to forage for shellfish in Khao Sam Roi Yot National Park in Thailand is affecting prey availability.

The researchers compared the availability, size and maturation stages of groups of shellfish between two islands inhabited by different-sized macaque populations against the stone artefacts uncovered on the island. In doing so, they were able to show how tool use has affected prey reproductive biology over time.

The findings show that this foraging behaviour has caused the monkeys to enter an 'ecological feedback loop', influencing both the size and amount of prey available over time. The evidence revealed an emerging pattern: both the size of the shellfish and the tools used to open them were found to be smaller on the island with many predators. If it continues, the researchers have speculated that these prey populations are likely to decline.

Without prey to forage on, the monkeys will also have no need to use the technique so might even experience a social regression and 'unlearn' how to use tools altogether.

Dr Luncz said: 'People often say that practice makes perfect – the more you do something the better you get at it. But the less you do it, the harder it becomes and the more you are likely to forget that skill completely. Our study shows that it is the same for monkeys. With no need to use the stones for foraging, the technique might be lost.

'As this is a learned social behaviour, in the long term there will be a generation of macaques that do not know how to use tools, and any associated benefit or trade with other species will be lost. Potentially, one day tool use might get reinvented by later generations, and it will be interesting to see how the skill is discovered and who they learn it from.

'This has interesting parallels to the evolution of human stone use, where stone technology might also have been lost and reinvented throughout history.'

The team will next build on this knowledge by visiting islands with monkey populations that do not currently use stone tools to dig for evidence that they may have done in the past.

Dr Luncz said: 'In archaeology, generally the deeper you dig the further you go back in time. The same methods used for human artefacts can tell us a lot about how species have evolved and adapted to environmental change over time.'

Source: University of Oxford [September 08, 2017]

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'Vampires' may have been real people with rare blood disorder

Porphyrias, a group of eight known blood disorders, affect the body's molecular machinery for making heme, which is a component of the oxygen-transporting protein, hemoglobin. When heme binds with iron, it gives blood its hallmark red color.

Mural of Vlad the Impaler, who was accused of being a vampire. Perhaps, instead, he suffered from 
a blood disorder called porphyria [Credit: Children's Hospital Boston]

The different genetic variations that affect heme production give rise to different clinical presentations of porphyria -- including one form that may be responsible for vampire folklore.

A clinical cause for nocturnal blood drinking?

Erythropoietic protoporphyria (EPP), the most common kind of porphyria to occur in childhood, causes people's skin to become very sensitive to light. Prolonged exposure to sunshine can cause painful, disfiguring blisters.

"People with EPP are chronically anemic, which makes them feel very tired and look very pale with increased photosensitivity because they can't come out in the daylight," says Barry Paw MD, PhD, of the Dana-Farber/Boston Children's Cancer and Blood Disorders Center. "Even on a cloudy day, there's enough ultraviolet light to cause blistering and disfigurement of the exposed body parts, ears and nose."

Staying indoors during the day and receiving blood transfusions containing sufficient heme levels can help alleviate some of the disorder's symptoms. In ancient times, drinking animal blood and emerging only at night may have achieved a similar effect -- adding further fuel to the legend of vampires.

Now, Paw and his team of international investigators report -- in a paper in the Proceedings of the National Academy of Sciences -- a newly discovered genetic mutation that triggers EPP. It illuminates a novel biological mechanism potentially responsible for stories of " vampires" and identifies a potential therapeutic target for treating EPP.

The nature of EPP's "supernatural" symptoms

To produce heme, the body goes through a process called porphyrin synthesis, which mainly occurs in the liver and bone marrow. Any genetic defects that impact this process can interrupt the body's ability to produce heme; the decreased heme production leads to a buildup of protoporphyrin components. In the case of EPP, type of protoporphyrin called protoporphrin IX accumulates in the red blood cells, plasma and sometimes the liver.

When protoporphin IX is exposed to light, it produces chemicals that damage surrounding cells. As a result, people with EPP experience swelling, burning and redness of the skin after exposure to sunlight -- even trace amounts of sunlight that pass through window glass.

Some genetic pathways leading to build-up of protoporphyrin IX have already been described, but many cases of EPP remain unexplained. By performing deep gene sequencing on members of a family from Northern France with EPP of a previously unknown genetic signature, Paw's team discovered a novel mutation of the gene CLPX, which plays a role in mitochondrial protein folding.

"This newly-discovered mutation really highlights the complex genetic network that underpins heme metabolism," says Paw, who was co-senior author on the study. "Loss-of-function mutations in any number of genes that are part of this network can result in devastating, disfiguring disorders."

Myth vs. reality

Paw suggests that identifying the various gene mutations that contribute to porphyria could pave the way for future therapies that could correct the faulty genes responsible for these related disorders.

"Although vampires aren't real, there is a real need for innovative therapies to improve the lives of people with porphyrias," says Paw.

Author: Kat J. McAlpine | Source: Boston Children's Hospital [September 07, 2017]

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How monkey fights grow

How does conflict spread through a society? One way to think of conflict spreading is to picture an epidemic, with aggressive individuals "infecting" others and causing them to join the fight.

A pigtail macaque shows its "game face" [Credit: A.J. Haverkamp]

While studying the dynamics of conflict in a monkey society, researchers Edward Lee (Cornell University), Bryan Daniels (ASU-SFI Center for Biosocial Complex Systems), David Krakauer (Santa Fe Institute), and Jessica Flack (Santa Fe Institute), found evidence for a more complicated structure behind conflict. Whereas the simple picture can be accurate for figuring out who will join a conflict, it is not enough to forecast how long the conflict will last. Their findings are published in a recent issue of the Journal of the Royal Society Interface.

Krakauer points out that if we view conflict as contagion, we might expect that the time it takes for a new conflict epidemic to die down would increase with each newly "infected" individual. In other words, each new participant simply adds to the total fight duration. Instead, Lee and colleagues found that fight durations grow more quickly as others join. It appears that it is not individuals who control the length of fights, but the relationships between pairs of individuals.

Imagine you are hosting a large dinner party. How long will you need to stay up? If the invitees are busy that week, each person might arrive at a different time but only stay for an hour. For each additional invitee, you simply add to the total duration of the party. But imagine that each person wants to talk with everyone else before leaving. If it is hard for more than a few conversations to happen at a time, then dinner will have to last until each pair of individuals has a chance to converse. This is how conflicts grow in duration, Lee says. More individuals mean more possibilities of conflict between pairs of individuals, and each of those pairwise relationships must be separately resolved.

Daniels says this finding suggests that "conflicts that grow big tend to get out of control," and "there are hints that a similar pattern may be at work in some human conflicts."

By studying statistical variation in the observed fights, the researchers found evidence that conflict duration is strongly affected by the first interaction, which sets the tone for the fight. If the first interaction is brief, then following episodes are likely to be just as brief. A long drawn out initial brawl, however, will be followed by similarly difficult episodes. This, Flack says, "is a signature of collective memory," meaning "the duration of the conflict is not just determined by individuals independently deciding whether to continue fighting or drop out, but through their joint memory for the past and subsequent collective decision-making."

Lee points out that interventions by uninvolved third-parties could be designed to stop conflicts that are likely to get out of control by watching closely how a fight starts and making a decision about when to intervene based on the features of this initial interaction. However, an open question is how much conflict to allow. Just as small fires in a forest clear out brush so that devastatingly large wildfires do not occur, small conflicts may play a useful role. By predicting how fights evolve, external monitors may be able to promote useful mild conflict but prevent harmful all-out brawls.

Source: Santa Fe Institute [September 07, 2017]

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