aDNA

Ancient genome 

from Africa 

sequenced 

for the first time 

Africa, Anthropology, ArchaeoHeritage, Archaeology, Breakingnews, Ethiopia, Genetics 


 The first ancient human genome from Africa to be sequenced has revealed that a wave of migration back into Africa from Western Eurasia around 3,000 years ago was up to twice as significant as previously thought, and affected the genetic make-up of populations across the entire African continent. The Mota cave is located in a mountainous region, and its entrance is about 6,000 feet  above sea level. 

Weather and the changing conditions of the only road that runs near  the cave -- a gravel surface -- made access complicated for the research team 

[Credit: Kathryn and John Arthur] 

The genome was taken from the skull of a man buried face-down 4,500 years ago in a cave called Mota in the highlands of Ethiopia -- a cave cool and dry enough to preserve his DNA for thousands of years. Previously, ancient genome analysis has been limited to samples from northern and arctic regions. The latest study is the first time an ancient human genome has been recovered and sequenced from Africa, the source of all human genetic diversity. The findings are published in the journal Science. The ancient genome predates a mysterious migratory event which occurred roughly 3,000 years ago, known as the 'Eurasian backflow', when people from regions of Western Eurasia such as the Near East and Anatolia suddenly flooded back into the Horn of Africa. 

Entrance to the Mota Cave in the Ethiopian highlands  

[Credit: Kathryn and John Arthur] 

The genome enabled researchers to run a millennia-spanning genetic comparison and determine that these Western Eurasians were closely related to the Early Neolithic farmers who had brought agriculture to Europe 4,000 years earlier. By comparing the ancient genome to DNA from modern Africans, the team have been able to show that not only do East African populations today have as much as 25% Eurasian ancestry from this event, but that African populations in all corners of the continent -- from the far West to the South -- have at least 5% of their genome traceable to the Eurasian migration. Researchers describe the findings as evidence that the 'backflow' event was of far greater size and influence than previously thought. The massive wave of migration was perhaps equivalent to over a quarter of the then population of the Horn of Africa, which hit the area and then dispersed genetically across the whole continent. 

The view looking out from the Mota cave in the Ethiopian highlands, where the remains containing the ancient genome were found  

[Credit: Kathryn and John Arthur] 

"Roughly speaking, the wave of West Eurasian migration back into the Horn of Africa could have been as much as 30% of the population that already lived there -- and that, to me, is mind-blowing. The question is: what got them moving all of a sudden?" said Dr Andrea Manica, senior author of the study from the University of Cambridge's Department of Zoology. Previous work on ancient genetics in Africa had involved trying to work back through the genomes of current populations, attempting to eliminate modern influences. "With an ancient genome, we have a direct window into the distant past. One genome from one individual can provide a picture of an entire population," said Manica. The cause of the West Eurasian migration back into Africa is currently a mystery, with no obvious climatic reasons. Archaeological evidence does, however, show the migration coincided with the arrival of Near Eastern crops into East Africa such as wheat and barley, suggesting the migrants helped develop new forms of agriculture in the region. 

In Mota cave, located in the Gamo highlands of Ethiopia, a group of NSF-supported  researchers excavation a rock cairn. They discovered under it a burial site  containing the remains of a 4,500-year skeleton  

[Credit: Kathryn and John Arthur] 

The researchers say it's clear that the Eurasian migrants were direct descendants of, or a very close population to, the Neolithic farmers that had had brought agriculture from the Near East into West Eurasia around 7,000 years ago, and then migrated into the Horn of Africa some 4,000 years later. "It's quite remarkable that genetically-speaking this is the same population that left the Near East several millennia previously," said Eppie Jones, a geneticist at Trinity College Dublin who led the laboratory work to sequence the genome. While the genetic make-up of the Near East has changed completely over the last few thousand years, the closest modern equivalents to these Neolithic migrants are Sardinians, probably because Sardinia is an isolated island, says Jones. "The famers found their way to Sardinia and created a bit of a time capsule. Sardinian ancestry is closest to the ancient Near East." "Genomes from this migration seeped right across the continent, way beyond East Africa, from the Yoruba on the western coast to the Mbuti in the heart of the Congo -- who show as much as 7% and 6% of their genomes respectively to be West Eurasian," said Marcos Gallego Llorente, first author of the study, also from Cambridge's Zoology Department. 

John Arthur, an NSF-supported archaeologist at the University  of South Florida St. Petersburg, excavates the Mota cave site  

[Credit: Kathryn and John Arthur]

 "Africa is a total melting pot. We know that the last 3,000 years saw a complete scrambling of population genetics in Africa. So being able to get a snapshot from before these migration events occurred is a big step," Gallego Llorente said. The ancient Mota genome allows researchers to jump to before another major African migration: the Bantu expansion, when speakers of an early Bantu language flowed out of West Africa and into central and southern areas around 3,000 years ago. Manica says the Bantu expansion may well have helped carry the Eurasian genomes to the continent's furthest corners. The researchers also identified genetic adaptations for living at altitude, and a lack of genes for lactose tolerance -- all genetic traits shared by the current populations of the Ethiopian highlands. In fact, the researchers found that modern inhabitants of the area highlands are direct descendants of the Mota man. Finding high-quality ancient DNA involves a lot of luck, says Dr Ron Pinhasi, co-senior author from University College Dublin. "It's hard to get your hands on remains that have been suitably preserved. The denser the bone, the more likely you are to find DNA that's been protected from degradation, so teeth are often used, but we found an even better bone -- the petrous." The petrous bone is a thick part of the temporal bone at the base of the skull, just behind the ear. "The sequencing of ancient genomes is still so new, and it's changing the way we reconstruct human origins," added Manica. "These new techniques will keep evolving, enabling us to gain an ever-clearer understanding of who our earliest ancestors were." The study was conducted by an international team of researchers, with permission from the Ethiopia's Ministry of Culture and Authority for Research and Conservation of Cultural Heritage. 

Source: University of Cambridge [October 08, 2015]

L'aiuto della Genetica

Using modern human genetics to study ancient phenomena 



Anthropology, Breakingnews, Genetics, Human Evolution 


We humans are obsessed with determining our origins, hoping to reveal a little of  “who we are” in the process. 

It is relatively simple to trace one’s genealogy back a few generations, and there are many companies and products offering such services. 

But what if we wanted to trace our origins further on an evolutionary timescale and study human evolution itself? In this case, there are no written records and censuses. Instead, the study of human evolution has so far relied heavily on fossil specimens and archaeological finds. 
Now, genetic tools and approaches are frequently used to answer evolutionary questions and reveal patterns of divergence that reflect different selective pressures and geographical movement. 
This is particularly true for studies of human migrations out of Africa, global population divergence, and its consequences for human health. 

Figure 1. Diagrammatic representation of the serial founder effect model  

[Credit: Emma Whittington] 

Humans Originated in Africa

The current best hypothesis suggests anatomically modern humans (AMH) arose in East Africa approximately 200,000 YBP (Years Before Present). 
AMH migrated from Africa around 100,000-60,000 years ago in a series of dispersals that expanded into Europe and Asia between 60,000 and 40,000 YBP. 
It has been scientifically proven that East Africa is the origin of humans, and supported by both archaeological and genetic data. 
Genetic diversity is greatest in East Africa and decreases in a step-wise fashion from the equator in a pattern reflecting sequential founder populations and bottlenecks. 



Figure 1 shows three populations with decreasing genetic diversity (represented by the colored circles) from left to right. The first population, with the greatest genetic diversity, represents Africa. A second population is shown migrating away from ‘Africa’ taking with it a sample of the existing genetic diversity. This forms the founding population for the next series of migrations. Each time a population migrates it represents only a sample of genetic variation existing in its founding population, and in doing so, sequential migration (such as those in Figure 1) leads to a reduction in genetic diversity with increasing distance from the first population. 

Leaving Africa – Where do we go from here? 

Although the location of human origin is generally accepted, there is a lack of consensus around the migration routes by which AMH left Africa and expanded globally. 
There are many studies using genetic tools to identify likely migration routes, one of which is a recent PLOS One article by Veerappa et al (2015). 
In this study, researchers characterized the global distribution of copy number variation, which is the variation in the number of copies of a particular gene, by high resolution genotyping of 1,115 individuals from 12 geographic populations, identifying 44,109 copy number variants (CNVs). 
The CNVs carried by an individual determined their CNV genotype and by comparing CNV genotypes between all individuals from all populations, the authors determined similarity and genetic distance between populations. 

The phylogenetic relationship between populations proposed a global migration map (Figure 2), in which an initial migration from the place of origin, Africa, formed a second settlement in East Asia, which is similar to a founding population seen in Figure 1. 

At least five further branching events took place in the second settlement, forming populations globally. The migration routes identified in this paper largely support those already proposed, but of particular interest this paper also proposes a novel migration route from Australia, across the Pacific, and towards the New World (shown in blue in Figure 2).

Figure 2. A global map showing CNV counts and possible migration routes  

[Credit: Veerappa et al (2015)] 

Global Migration Leads to Global Variation As AMH spread across the globe, populations diverged and encountered novel selective pressures to which they had to adapt. This is reflected in the phenotypic (or observable) variation seen between geographically distant populations. 
At the genotype level, a number of these traits show evidence of positive selection, meaning they likely conferred some advantage in particular environments and were consequently favored by natural selection and increased in frequency. 
A well cited example of this is global variation in skin color, which is thought to reflect a balance between vitamin D synthesis and photoprotection (Figure 3). 

Vitamin D synthesis requires UV radiation, and a deficiency in vitamin D can result in rickets, osteoporosis, pelvic abnormalities, and a higher incidence of other diseases. 

At higher latitudes, where UV radiation is low or seasonal, experiencing enough UV radiation for sufficient vitamin D synthesis is a major concern. 
Presumably, as AMHs migrated from Africa, they experienced reduced levels of UV radiation, insufficient vitamin D synthesis, and severe health problems; resulting in selection for increased vitamin D synthesis and lighter skin pigmentation. 
Consistent with this, a number of pigmentation genes underlying variation in skin color show evidence of positive selection  in European and Asian populations, relative to Africa. 

On the flip side, populations near the equator experience no shortage of UV radiation and thus synthesize sufficient vitamin D; however the risk of UV damage is much greater. Melanin, the molecule determining skin pigmentation, acts as a photoprotective filter, reducing light penetration and damage caused by UV radiation, resulting in greater photoprotection in darkly pigmented skin. 
Selective pressure to maintain dark pigmentation in regions with high UV radiation is evident by the lack of genetic variation in pigment genes in areas such as Africa. 
This suggests selection has acted to remove mutation and maintain the function of these genes.

Figure 3. A map showing predominant skin pigmentation globally  

[Credit: Barsch (2003)]

 Can genetics and human evolution have a practical use in human health? 
Beyond phenotypic consequences, genetic variation between populations has a profound impact on human health. 
It has a direct influence on an individual’s predisposition for certain conditions or diseases. For example, Type 2 diabetes is more prevalent in African Americans than Americans of European descent. 
Genome wide association studies (GWAS) analyze common genetic variants in different individuals and assess whether particular variants are more often associated with certain traits or diseases. 
Comparing the distribution and number of disease-associated variants between populations can assess if genetic risk factors underlie disparities in disease susceptibility. In the case of Type 2 diabetes, African Americans carry a greater number of risk variants than Americans of European descent at genetic locations (loci) associated with Type 2 diabetes. 
It is clear that an individual’s ethnicity affects their susceptibility and likely reaction to disease, and as such should be considered in human health policy. 
Understanding the genetic risk factors linking populations and disease can identify groups of individual at greater risk of developing certain diseases for the sake of prioritizing treatment and prevention. 
Applying modern human genetics to human evolution has opened a door to studying ancient evolutionary phenomena and patterns. 
This area not only serves to quench the desire to understand our origins, but profoundly impacts human health in a way that could revolutionize disease treatment and prevention. 

In this blog, I have given a brief overview of how using genetic approaches can tell us a great deal about human origins, migration and variation between populations. 
In addition, I have outlined the complex genetic underpinnings behind ethnicity and disease susceptibility, which suggests an important role for population genetics in human health policy. 
This blog post covers only a fraction of the vast amount of ongoing work in this field, and the often ground breaking findings. 
It is unclear exactly how far genetics will take us in understanding human evolution, but the end is far from near. The potential for genetics in this field and broader feels limitless, and I for one am excited by the prospect. 

Author: Emma Whittington | Source: PLOS Blogs [August 01, 2015]

Lingua e Geni

Scientists discover links between genes and language 


Anthropology, ArchaeoHeritage, Archaeology, Breakingnews, Genetics, Linguistics 


Academics at the University of York have discovered a correlation between genetic and linguistic diversity and concluded that at least in Europe people who speak different languages are also more likely to have a different genetic make-up. 

Multilingual Europe, showing the genealogy of the languages, together with  the alphabets and modes of writing of all peoples by Gottfried Hensel 

 [Credit: WikiCommons] 

The study, led by Professor Giuseppe Longobardi  in York’s Department of Language and Linguistic Science, in collaboration with geneticists and linguists at the Universities of Ferrara and Modena and Reggio Emilia in Italy, has discovered that language proves a better predictor of genetic differences than the geographical distribution of population. As part of his study he observed significant correlations between genetic and linguistic diversity across the Indo-European and non-Indo-European-speaking populations of Europe. 
Professor Longobardi said: “To a very large extent linguistic differences correspond to genetic differences in the relevant populations.  So, if a population speaks French and another speaks Russian they have a certain degree of linguistic diversity, that we can now measure with unprecedented precision and the degree of genetic diversity is proportional. “Is it the case that the French and Italians and Spanish, who speak very close languages, are really similar to each other in genetic terms?  
Is it really the case the Japanese, and say a population from Sub Saharan Africa, are really very different  both in terms of language and in terms of their genetic ancestry ? 
To some extent our answer, based on the published study and further work in progress, is yes: at least as a general historical rule.” 
However, Professor Longobardi said there are exceptions, as to many rules, and the exception in Europe is the Hungarians,  who are genetically very similar to Slavic and Germanic populations. 
“That’s one case where some populations of central Europe  just picked up a new language  which was brought in to Hungary by a small group of conquerors. 
“But apart from that exception the distribution of languages and the distribution of the genetic structure of the populations in Europe tend to correspond to each other,” he added. The study, published in the American Journal of Physical Anthropology, suggests that migrating populations carried their genes alongside their language, rather than just a cultural diffusion of linguistic features from one population to another. 
The project involved studying around 15 European languages but researchers are turning their attention to other languages, extending potentially to a global scale. 
The research could eventually help scientists pinpoint when and how Indo-European languages were brought into Europe and potentially help geneticists in the future. Professor Longobardi added: “Ultimately being able to identify the ancestry of a population just on the simple basis of the language they speak may benefit identifying genetic properties of these populations, which could ultimately be of practical use even for medical research.” 


Source: University of York [July 03, 2015]

Decorato con il latte

South Africans used 

milk-based paint 

49,000 years ago 

Anthropology, ArchaeoHeritage, Archaeology, Breakingnews, Early Humans, South Africa 

An international research team led by the University of Colorado Boulder and the University of Witwatersrand in Johannesburg, South Africa has discovered a milk-and ochre-based paint dating to 49,000 years ago that inhabitants may have used to adorn themselves with or to decorate stone or wooden slabs. 

(A) MOD flake before sampling, scale bar = 1 cm. (B) Detail of residue left after  sampling for chemical and proteomic analyses. (C) View at 40 x. (D) View at 128 x  [Credit: Villa et al. PLOS ONE, 2015; DOI: 10.1371/journal.pone.0131273] 

While the use of ochre by early humans dates to at least 250,000 years ago in Europe and Africa, this is the first time a paint containing ochre and milk has ever been found in association with early humans in South Africa, said Paola Villa, a curator at the University of Colorado Museum of Natural History and lead study author. 

The milk likely was obtained by killing lactating members of the bovid family such as buffalo, eland, kudu and impala, she said. "Although the use of the paint still remains uncertain, this surprising find establishes the use of milk with ochre well before the introduction of domestic cattle in South Africa," said Villa. "Obtaining milk from a lactating wild bovid also suggests that the people may have attributed a special significance and value to that product." 

The powdered paint mixture was found on the edge of a small stone flake in a layer of Sibudu Cave, a rock shelter in northern KwaZulu-Natal, Africa, that was occupied by anatomically modern humans in the Middle Stone Age from roughly 77,000 years ago to about 38,000 years ago, said Villa. 

While ochre powder production and its use are documented in a number of Middle Stone Age South African sites, there has been no evidence of the use of milk as a chemical binding agent until this discovery, she said. 
A paper on the subject was published online June 30 in PLOS ONE. Co-authors were from the Italian Institute of Paleontology in Rome, Italy; the University of Geneva in Switzerland; the University of Pisa in Italy; the University of Monte St. Angelo in Naples, Italy; and the University of Oxford in England. The excavation was directed by Professor Lyn Wadley of the University of Witwatersrand, also a paper co-author. Cattle were not domesticated in South Africa until 1,000 to 2,000 years ago, said Villa. Wild South African bovids are known to separate from the herd when giving birth and usually attempt to hide their young, a behavior that may have made them easy prey for experienced Middle Stone Age hunters, she said. 

The dried paint compound is preserved on the stone flake that may have been used as a mixing implement to combine ochre and milk, or as an applicator, said Villa. 

The team used several high-tech chemical and elemental analyses to verify the presence of casein, the major protein of milk, on the flake. At both African and European archaeological sites, scientists have found evidence of ochre -- a natural pigment containing iron oxide than can range from yellow and orange to red and brown -- dating back 250,000 
years.

By 125,000 years ago, there is evidence ochre was being ground up to produce a paint powder in South Africa. 

It has been proposed the ochre was sometimes combined by ancient Africans with resin or plant gum to use as an adhesive for attaching shafts to stone tools or wooden bone handles, Villa said. It also may have been used to preserve hides and for body paint, she said, noting that a roughly 100,000-year-old ochre-rich compound blended with animal marrow fat was found at the Middle Stone Age site of Blombos Cave in South Africa. 

Body painting is widely practiced by the indigenous San people in South Africa, and is depicted in ancient rock art. While there are no ethnographic precedents for mixing ochre with milk as a body paint, the modern Himba people in Namibia mix ochre with butter as a coloring agent for skin, hair and leather clothing, Villa said. 

Source: University of Colorado at Boulder [June 30, 2015]

I più antichi strumenti di pietra: Kenyantropo?

World's oldest stone tools 

challenge ideas about 

first toolmakers 

Scientists working in the desert badlands of northwestern Kenya have found stone tools dating back 3.3 million years, long before the advent of modern humans, and by far the oldest such artifacts yet discovered. 

The tools, whose makers may or may not have been some sort of human ancestor, push the known date of such tools back by 700,000 years; they also may challenge the notion that our own most direct ancestors were the first to bang two rocks together to create a new technology. 

Tool unearthed at excavation site [Credit: MPK-WTAP] 

The discovery is the first evidence that an even earlier group of proto-humans may have had the thinking abilities needed to figure out how to make sharp-edged tools. 

The stone tools mark "a new beginning to the known archaeological record," say the authors of a new paper about the discovery, published today in the leading scientific journal Nature. 

"The whole site's surprising, it just rewrites the book on a lot of things that we thought were true," said geologist Chris Lepre of the Lamont-Doherty Earth Observatory and Rutgers University, a co-author of the paper who precisely dated the artifacts. 
The tools "shed light on an unexpected and previously unknown period of hominin behavior and can tell us a lot about cognitive development in our ancestors that we can't understand from fossils alone," said lead author Sonia Harmand, of the Turkana Basin Institute at Stony Brook University and the Universite Paris Ouest Nanterre. 

Hominins are a group of species that includes modern humans, Homo sapiens, and our closest evolutionary ancestors. 

Anthropologists long thought that our relatives in the genus Homo - the line leading directly to Homo sapiens - were the first to craft such stone tools. 

But researchers have been uncovering tantalizing clues that some other, earlier species of hominin, distant cousins, if you will, might have figured it out. 
The researchers do not know who made these oldest of tools. But earlier finds suggest a possible answer: 
The skull of a 3.3-million-year-old hominin, Kenyanthropus platytops, was found in 1999 about a kilometer from the tool site. A K. platyops tooth and a bone from a skull were discovered a few hundred meters away, and an as-yet unidentified tooth has been found about 100 meters away. 

Sammy Lokorodi, a resident of Kenya's northwestern desert who works as a fossil  and artifact hunter, led the way to a trove of 3.3 million-year-old tools  

[Credit: West Turkana Archaeological Project] 

The precise family tree of modern humans is contentious, and so far, no one knows exactly how K. platyops relates to other hominin species. Kenyanthropus predates the earliest known Homo species by a half a million years. 

- This species could have made the tools; or, the toolmaker could have been some other species from the same era, such as Australopithecus afarensis, or an as-yet undiscovered early type of Homo.
 Lepre said a layer of volcanic ash below the tool site set a "floor" on the site's age: It matched ash elsewhere that had been dated to about 3.3 million years ago, based on the ratio of argon isotopes in the material. 
To more sharply define the time period of the tools, Lepre and co-author and Lamont-Doherty colleague Dennis Kent examined magnetic minerals beneath, around and above the spots where the tools were found. 
The Earth's magnetic field periodically reverses itself, and the chronology of those changes is well documented going back millions of years. 
"We essentially have a magnetic tape recorder that records the magnetic field ... the music of the outer core," Kent said. By tracing the variations in the polarity of the samples, they dated the site to 3.33 million to 3.11 million years. 
Another co-author, Rhonda Quinn of Seton Hall University, studied carbon isotopes in the soil, which along with animal fossils at the site allowed researchers to reconstruct the area’s vegetation. 
This led to another surprise: 
- The area was at that time a partially wooded, shrubby environment. Conventional thinking has been that sophisticated tool-making came in response to a change in climate that led to the spread of broad savannah grasslands, and the consequent evolution of large groups of animals that could serve as a source of food for human ancestors. 
- One line of thinking is that hominins started knapping - banging one rock against another to make sharp-edged stones - so they could cut meat off of animal carcasses, said paper co-author Jason Lewis of the Turkana Basin Institute and Rutgers. 
But the size and markings of the newly discovered tools "suggest they were doing something different as well, especially if they were in a more wooded environment with access to various plant resources," Lewis said. 
The researchers think the tools could have been used for breaking open nuts or tubers, bashing open dead logs to get at insects inside, or maybe something not yet thought of. 

Chris Lepre of Columbia University's Lamont-Doherty Earth Observatory  precisely dated the artifacts by analyzing layers above, around  and below them for reversals in earth's magnetic field  

[Credit: West Turkana Archaeological Project] 

"The capabilities of our ancestors and the environmental forces leading to early stone technology are a great scientific mystery," said Richard Potts, director of the Human Origins Program at the Smithsonian's National Museum of Natural History, who was not involved in the research. 
The newly dated tools "begin to lift the veil on that mystery, at an earlier time than expected," he said. 
Potts said he had examined the stone tools during a visit to Kenya in February. "Researchers have thought there must be some way of flaking stone that preceded the simplest tools known until now," he said. 
"Harmand's team shows us just what this even simpler altering of rocks looked like before technology became a fundamental part of early human behavior." 

- Ancient stone artifacts from East Africa were first uncovered at Olduvai Gorge in Tanzania in the mid-20th century, and those tools were later associated with fossil discoveries in the 1960s of the early human ancestor Homo habilis.
 That species has been dated to 2.1 million to 1.5 million years ago. 
Subsequent finds have pushed back the dates of humans' evolutionary ancestors, and of stone tools, raising questions about who first made that cognitive leap. 
- The discovery of a partial lower jaw in the Afar region of Ethiopia, announced on March 4, pushes the fossil record for the genus Homo to 2.8 million years ago. Evidence from recent papers, the authors note, suggests that there is anatomical evidence that Homo had evolved into several distinct lines by 2 million years ago. There is some evidence of more primitive tool use going back even before the new find. 
- In 2009, researchers at Dikika, Ethiopia, dug up 3.39 million-year-old animal bones marked with slashes and other cut marks, evidence that someone used stones to trim flesh from bone and perhaps crush bones to get at the marrow inside. 
That is the earliest evidence of meat and marrow consumption by hominins. 
No tools were found at the site, so it's unclear whether the marks were made with crafted tools or simply sharp-edged stones. 
The only hominin fossil remains in the area dating to that time are from Australopithecus afarensis. 

The skull of a 3.3-million-year-old hominin, Kenyanthropus platyops,  was found in 1999 about a kilometer from the tool site  

[Credit: Bone Clones® Kenyanthropus platyops Skull]

 The new find came about almost by accident: Harmand and Lewis said that on the morning of July 9, 2011, they had wandered off on the wrong path, and climbed a hill to scout a fresh route back to their intended track. 
They wrote that they "could feel that something was special about this particular place." They fanned out and surveyed a nearby patch of craggy outcrops. "By teatime," they wrote, "local Turkana tribesman Sammy Lokorodi had helped [us] spot what [we] had come searching for." 
By the end of the 2012 field season, excavations at the site, named Lomekwi 3, had uncovered 149 stone artifacts tied to tool-making, from stone cores and flakes to rocks used for hammering and others possibly used as anvils to strike on. 
The researchers tried knapping stones themselves to better understand how the tools they found might have been made. 
They concluded that the techniques used "could represent a technological stage between a hypothetical pounding-oriented stone tool use by an earlier hominin and the flaking-oriented knapping behavior of [later] toolmakers." 

Chimpanzees and other primates are known to use a stone to hammer open nuts atop another stone. But using a stone for multiple purposes, and using one to crack apart another into a sharper tool, is more advanced behavior. 

The find also has implications for understanding the evolution of the human brain. 
The toolmaking required a level of hand motor control that suggests that changes in the brain and spinal tract needed for such activity could have occurred before 3.3 million years ago, the authors said. "This is a momentous and well-researched discovery," said paleoanthropologist Bernard Wood of George Washington University, who was not involved in the study. "I have seen some of these artifacts in the flesh, and I am convinced they were fashioned deliberately." 
Wood said he found it intriguing to see how different the tools are from so-called Oldowan stone tools, which up to now have been considered the oldest and most primitive. The finds were made in the desert badlands near Lake Turkana, Kenya.

 Many  other important discoveries of fossils and artifacts have been made nearby  [Credit: West Turkana Archaeological Project] 

Lepre, who has been conducting fieldwork in eastern Africa for about 15 years, said he arrived at the dig site about a week after the discovery. 
The site is several hours' drive on rough roads from the nearest town, located in a hot, dry landscape he said is reminiscent of Arizona and New Mexico. Lepre collected chunks of sediment from a series of depths and brought them back to Lamont-Doherty for analysis. He and Kent used a bandsaw to trim the samples into sugar cube-size blocks and inserted them into a magnetometer, which measured the polarity of tiny grains of the minerals hematite and magnetite contained in the sediment.
 "The magnetics pretty much clinches that the age is something like 3.3 million years old," said Kent, who also is a professor at Rutgers. 
Earlier dating work by Lepre and Kent helped lead to another landmark paper in 2011: a study that suggested Homo erectus, another precursor to modern humans, was using more advanced tool-making methods 1.8 million years ago, at least 300,000 years earlier than previously thought. 
"I realized when you [figure out] these things, you don't solve anything, you just open up new questions," said Lepre. "I get excited, then realize there's a lot more work to do." 

Source: The Earth Institute at Columbia University [May 20, 2015]

Il sangue umano più antico.

- Due ferite: una di freccia e l'altra un taglio sulla mano destra.  Sono state esaminate con una sonda nanotecnologica avanzatissima, che ha identificato con laser-scanner la tipica forma a concavità doppia dei globuli rossi...

- Il sangue umano in oggetto è il più antico mai trovato (5.300 anni fa circa) con certezza (altri reperti dell'età della pietra, su strumenti ed altro, non sono certi, in quanto varie altre entità possiedono forme analoghe al globulo rosso: grani di polline, batteri etc e con esso potrebbero essere state confuse). 

- La certezza. In questo caso, la rifrazione della luce del laser ha permesso di identificare con precisione una proteina tipica ed esclusiva del globulo rosso (emoglobina) ed una sostanza coagulante (fibrina.)

- Si tratta di un omicidio di 5.000 anni fa, per cause sconosciute: un uomo fu ucciso da una freccia scagliata con l'arco. Il caso di Iceman Otzi è un vero 'cold case' e s'indaga ancora... 

- La sua morte fu rapida dopo neanche qualche minuto; se fu dolorosa, ebbene: non soffrì a lungo. Questo si può affermare proprio per via della presenza della fibrina: quest'ultima si forma immediatamente, subito dopo la lesione. In un corpo vivo, però, scompare e viene riassorbita dopo pochi minuti.

- L'articolo dell'avanzatissima indagine è comparso sulla rivista Interface, autore Albert Zink, capo dell'Istituto per le mummie e per l'Icemen, di Bolzano, Italia. 

World's oldest blood found 

in famed

 "Iceman" mummy 



The world's oldest known blood cells have been found on Ötzi the Iceman, according to the latest research on the 5,300-year-old mummy. 
What's more, the discovery proves that the Stone Age homicide victim had a quick, if not painless, death. 

AFM images of red blood cells (RBCs). 

(a,b) Single RBCs from recent human tissue. (c) An assembly of RBCs. (d,e) Single corpuscles found in Iceman sample A and  sample B are shown. An assembly of several randomly distributed corpuscles,  similar to those found within the recent sample (c), are displayed in image (f). The imaged corpuscles (d–f) feature the characteristic discoid and concave  surface of RBCs 

[Credit: Journal of the Royal Society Interface] 

Ötzi has been the subject of extensive postmortem investigations ever since his corpse was discovered in an Alpine glacier on the Austrian-Italian border in 1991. 

No blood residue had previously been detected, however, despite various studies detailing his violent death due to an arrow shot and other injuries. 

"There were no [blood] traces found, even when they opened some arteries, so it was thought maybe the blood had not preserved and had completely degraded, or that he lost too much blood because of the arrow injury" on his back, said team member Albert Zink, head of the Institute for Mummies and the Iceman in Bolzano, Italy. 

For the new investigation, scientists traced Ötzi's wound areas—the arrow injury and a cut on his right hand—with a pioneering nano-size probe. 
Each minute movement of the probe was recorded with a laser, "so you get a three-dimensional image of the sample in a very tiny scale," Zink explained. The scans revealed classic "doughnut shape" red blood cells, the team reported Wednesday in the journal Interface.

While past studies have suggested evidence for prehistoric blood on Stone Age tools and other artifacts, "you can never really be sure, because you can see structures which are quite similar to red blood cells" such as pollen grains or bacteria, Zink commented. 

Ötzi the Iceman's mummified remains (shown above) were found on a glacier  on the Italian and Austrian border in 1991. Researchers have now discovered traces  of a molecule involved in blood clotting on the body, suggesting he bled rapidly  to death from an arrow wound to his shoulder 

[Credit: Reuters] 

To confirm they were indeed dealing with human blood cells, the researchers illuminated the wounds with a laser. The wavelengths of the scattered light revealed the substances' molecular makeup. 
"We got very typical samples for blood, like for the [blood protein] hemoglobin," he said. The new finding "really is the oldest clear evidence for red blood cells.

" The new nanotechnology, allied with an atomic force microscope, also uncovered traces of fibrin, a blood-clotting agent—evidence that the Iceman suffered a mercifully quick demise. 

"Fibrin is formed immediately when you get a wound, within a few minutes, but then it disappears"—in a living, functioning body, anyway, Zink said. 

"Finding fibrin in the arrow wound is confirmation that Ötzi actually died very quickly after the arrowshot."

"There were still some people arguing that he survived the arrow maybe a few hours or a few days, but this was definitely not true," he added. 

The relatively new techniques used in the study may in the future assist in the investigation of modern-day homicides. Since old blood cells are more elastic than fresh samples, the same blood-analysis techniques could become useful at crime scenes, Zink said. "If the blood is dry, forensic science really has no good method for determining the age of blood spots ... They cannot say if it is a day, a week, or a month old," he said. "If you can record with this technology little differences in the elasticity of the structure, then you can maybe determine the age of the blood spot." 

Author: James Owen | Source: National Geographic News 

[May 08, 2015]