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DNA study to investigate the other 99% of Romans

Who were Rome’s 99%? How did the common people experience life in the Imperial capital? Dr. Kristina Killgrove of Vanderbilt University is filling in the gaps of history by studying the skeletons of Rome’s lower class denizens.

Ancient Roman [Credit: Dr. Kristina Killgrove]

Since 2007, Dr. Killgrove has been employing biochemical analyses of human skeletal material to learn more about the diet, disease, and origins of people buried in two suburban Roman cemeteries. Her research with stable isotopes has shown that men, women, and children immigrated to the city, that they ate many different kinds of food, and that several of them suffered from lead poisoning.

The Roman DNA Project, which Dr. Killgrove launched at the beginning of November, is the next step in understanding the average inhabitants of the city. With the collaboration of aDNA expert Dr. John Dudgeon of Idaho State University, Dr. Killgrove will examine the molecular structure of people who died nearly two millennia ago in Rome. This project is the first to sequence DNA from the inhabitants of Imperial Rome and will reveal more about the origins of immigrants to the city.

Dr. Kristina Killgrove at Pompeii [Credit: Dr. Kristina Killgrove]

Dr. Killgrove is seeking financing for this pilot project directly from the public. As part of the SciFund Challenge, a collection of 49 scientists from around the world who are crowdfunding their research this winter, the Roman DNA Project has already raised nearly half of the $6,000 needed to undertake aDNA analysis. Have you ever wanted to receive a letter from an ancient Roman? Donors to this fund drive can choose from rewards that feature the skeletal remains of the ancient Romans themselves.

Unlike the 99% in the U.S., who can make their voices heard via protests and media, Rome’s lower classes had almost no power to effect change in their society. The Roman DNA Project seeks to adjust the balance of history and tell the stories of the commoners at Rome.

Author/Source: Dr. Kristina Killgrove [November 11, 2011]

Modern humans arrived earlier in Southern Europe than previously believed

Virtual Anthropology allows new identification of first modern humans – Members of our species (Homo sapiens) arrived in Europe several millennia earlier than previously thought. At this conclusion a team of researchers, led by the Department of Anthropology, University of Vienna, arrived after re-analyses of two ancient deciduous teeth.

Mesial view of the specimen Cavallo-B (deciduous left upper first molar), the first European anatomically modern human. The white bar in the figure is equivalent to 1 cm [Credit: Stefano Benazzi]

These teeth were discovered 1964 in the "Grotta del Cavallo", a prehistoric cave in southern Italy. Since their discovery they have been attributed to Neanderthals, but this new study suggests they belong to anatomically modern humans.

Chronometric analysis, carried out by the Oxford Radiocarbon Accelerator Unit at the University of Oxford, shows that the layers within which the teeth were found date to ~43,000-45,000 cal BP. This means that the human remains are older than any other known European modern humans. The research work was published in the renowned science journal Nature.

Grotta del Cavallo, in Apulia, was discovered in 1960. It contained about 7 m of archaeological deposits spanning the period during which Neanderthals were replaced by modern humans. Two milk teeth were unearthed in 1964 by Arturo Palma di Cesnola (emeritus of the University of Siena) from the so-called Uluzzian archaeological layers.

The Uluzzian culture has been described from more than 20 separate sites across Italy, and is characterised by personal ornaments, bone tools and colourants; items typically associated with modern human symbolic behaviour. But the teeth from Cavallo were identified in the 1960's as Neanderthals who lived around 200,000 to 40,000 years ago. This attribution has been at the heart of a widely held consensus that the Uluzzian and the complex ornaments and tools within it were also produced by Neanderthals.

Comparison of micro-computed-tomography scans of teeth

Stefano Benazzi, post-doc at the Department of Anthropology at University of Vienna, and his colleagues were able to compare digital models derived from micro-computed tomography scans of the human remains from Grotta del Cavallo with those of a large modern human and Neanderthal dental sample:

Three-dimensional digital model of Cavallo-B (deciduous left upper first molar). Enamel is transparent to show the crown dentine [Credit: Stefano Benazzi]

"We worked with two independent methods: for the one, we measured the thickness of the tooth enamel, and for the other, the general outline of the crown. By means of micro-computed tomography it was possible to compare the internal and external features of the dental crown. The results clearly show that the specimens from Grotta del Cavallo were modern humans, not Neanderthals as originally thought."

New chronometric analyses of the Oxford Radiocarbon Accelerator Unit

Katerina Douka, post-doc at the Research Laboratory for Archaeology and History of Art at the University of Oxford, undertook a comprehensive programme of radiocarbon dating to establish a firm chronology for the finds. Previous dates for the Uluzzian were problematic and affected by contamination. Since the teeth were too small to date directly, Douka developed a new approach that focused on the dating of marine shells found in the same archaeological levels as the teeth.

Uluzzian artifacts from Grotta del Cavallo, Apulia, southern Italy [Credit: Annamaria Ronchitelli and Katerina Douka]

This approach showed that the modern human teeth must date to between ~43,000-45,000 years ago. Douka said, "Radiocarbon dating of Palaeolithic material is difficult because the levels of remaining radiocarbon are very low and contamination can be problematic. Shell beads are important objects of body ornamentation and have allowed us directly and reliably radiocarbon date items associated with these early Homo sapiens settlers of Europe."

Uluzzian culture was made by modern humans

"What the new dates mean", Benazzi summarised, "is that these two teeth from Grotta del Cavallo represent the oldest European modern human fossils currently known. This find confirms that the arrival of our species on the continent – and thus the period of coexistence with Neanderthals – was several thousand years longer than previously thought.

Grotta del Cavallo (red arrow) opens on the bay of Uluzzo, which is located in the Regional Natural Park of Portoselvaggio, Apulia, southern Italy [Credit: Annamaria Ronchitelli]

Based on this fossil evidence, we have confirmed that modern humans and not Neanderthals are the makers of the Uluzzian culture. This has important implications to our understanding of the development of 'fully modern' human behaviour. Whether the colonisation of the continent occurred in one or more waves of expansion and which routes were followed is still to be established."

International collaboration makes it possible

Gerhard Weber, head of the Core Facility for Micro-Computed Tomography and deputy head of the Department of Anthropology at University of Vienna, commented on the discovery in the following way: "Human fossil material is very rare, particularly well preserved deciduous teeth. It is only thanks to the collaboration of several European institutions that fossil remains were accessible.

The re-evaluation of the Cavallo material was only made possible through technical innovations developed in the last decade, known as 'Virtual Anthropology'. These new techniques developed for dental morphometrics and also new radiocarbon dating will help to address taxonomic questions associated with other contentious human fossil remains."

Source: University of Vienna [November 02, 2011]

'Zombie' worms found in Mediterranean fossil

Traces of bizarre, bone-eating ‘zombie’ worms have been found on a three million year old fossil whale bone from Tuscany in Italy.

A computer-generated reconstruction of the Osedax worm responsible for borings found in a fossil whale bone in the Mediterranean, showing its root-like tissues used for feeding [Credit: Image courtesy of University of Leeds]

It is the first time the genus Osedax has been found in the Mediterranean, and suggests Osedax were widespread throughout the world's oceans 6 million years ago.

The new find, published in the journal Historical Biology, confirms what scientists have long suspected - that Osedax were likely responsible for erasing parts of the fossil record by destroying bones before they could become fossils.

Worms from the Osedax genus do not have a mouth or gut but consume the bone by growing root-like tissues, which dissolve the bone as they grow.

Lead scientist Nicholas Higgs discovered tell-tale traces of Osedax in the Mediterranean last year using micro-CT (Computed Tomography) scanning technology as part of his PhD at the University of Leeds and the Natural History Museum.

He says: "After several promising leads came to a dead end, the scans from the final sample looked different and I knew that I was on to something."

Osedax were first discovered alive in 2002 in Monterey Bay, California, where they were living on the bones of a decaying gray whale.

Since then, scientists have been curious about how the worms might have affected fossil records, but understanding when Osedax evolved and where they lived in the past has until now remained a problem because actual remains of soft-bodied Osedax do not preserve as fossils.

The only way to tell where and when Osedax have been at work is by distinctive bulb-shaped cavities that they leave behind in a bone - and it is these borings that have finally been recognised by Higgs.

His research shows how widespread Osedax were millions of years ago.

The only other known evidence of Osedax from the past is in whale bones from the Pacific coast of Washington State in the US - about as far away as it is possible to get from the Mediterranean in terms of ocean connectedness.

When Mediterranean dried up almost six million years ago most deep sea animals were killed. About half a million years later the sea re-flooded from the Atlantic.

Higgs says: "So finding out that Osedax were feeding on this whale bone three million years ago tell us that their ancestors must have also been living in the Atlantic as well, because the Mediterranean was re-colonised 5.5 million years ago from the Atlantic."

It is now almost certain that the Mediterranean is currently host to undiscovered, living Osedax species, Higgs says.

"There are 20 different species in Monterey, California alone, so it's almost certain there are many more out there. If Osedax were living the Mediterranean three million years ago there's no reason why they aren't living there now."

Last year, Higgs travelled to California to examine living Osedax and their borings to help understand and identify the full range of known species.

Source: University of Leeds [November 01, 2011]

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DNA study to investigate the other 99% of Romans

Modern humans arrived earlier in Southern Europe than previously believed

'Zombie' worms found in Mediterranean fossil

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