18th Dynasty shaft tomb discovered in Gebel el-Silsila

The Swedish-Egyptian mission at Gebel el-Silsila, Aswan Region, led by Dr. Maria Nilsson and John Ward (Lund University), under the supervision of the inspectorates of Aswan and Kom Ombo, has discovered an undecorated shaft tomb (5m deep) with two chambers dating to the 18th Dynasty (Thutmosid period).

18th Dynasty shaft tomb discovered in Gebel el-Silsila
The team (l-r: Ibrahim, John, Ali, Ahmed) prepare one of the child sarcophagi to be lifted
[Credit: Gebel el Silsila Project]

The tomb is water filled and requires pumping to allow excavations. Since a recent looting attempt the tomb is also filled with sand and silt, and the extent of damage that was caused to the monument is still to be assessed.
Mr. Abdel Moniem, General Director of Aswan and Nubia, says that the team is currently estimating the preservation of the tomb, as the movement of water and sand has caused great disturbance to the interior, artefacts and osteological remains, but it appears to be intact and undisturbed from looting.

18th Dynasty shaft tomb discovered in Gebel el-Silsila
ST42 interior southern wall with niche [Credit: Gebel el Silsila Project]
18th Dynasty shaft tomb discovered in Gebel el-Silsila
Lotus-shaped amulet [Credit: Gebel el Silsila Project]

18th Dynasty shaft tomb discovered in Gebel el-Silsila
Men-Kheper-Re scarab [Credit: Gebel el Silsila Project/Anders Andersson]
18th Dynasty shaft tomb discovered in Gebel el-Silsila
Shabti figure [Credit: Gebel el Silsila Project]
18th Dynasty shaft tomb discovered in Gebel el-Silsila
Hair bead [Credit: Gebel el Silsila Project]

So far, the team has discovered three sandstone sarcophagi, two of which have been excavated, revealing an infant and a young child. The third sarcophagus was also made for an infant; its contents await excavation.
Chronologically, there are indications of at least three generations, ranging from Thutmosis II to Amenhotep II (c. 3400 years ago). Exceptionally, the team has documented the remains of so far a minimum of over 60 individuals (2/3 adults and 1/3 children) which have been discovered, but with excavations still ongoing the team estimates the amount to increase.

18th Dynasty shaft tomb discovered in Gebel el-Silsila
Water being pumped out of the tomb to allow excavation
[Credit: Gebel el Silsila Project]

No other tomb previously documented at Gebel el-Silsila has contained such a high number of entombed individuals. One of the more important results of the discovery at Gebel el-Silsila is the amount of buried children and women, indicating that there was a complete society with entire families living and working in ancient Kheny. Excavations are scheduled to continue until the end of the year.

Source: Gebel el Silsila Project [December 14, 2018]

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Neanderthal genes influence brain development of modern humans

A characteristic feature of modern humans is the unusually round skull and brain, in contrast to the elongated shape seen in other human species. By studying Neanderthal DNA fragments found in the genomes of living Europeans, scientists have now discovered genes that influence this globular shape. An interdisciplinary research team, led by the Max Planck Institutes for Psycholinguistics and Evolutionary Anthropology, brought together fossil skull data, brain imaging and genomics, as reported in Current Biology.

Neanderthal genes influence brain development of modern humans
Computed tomographic scan of a Neanderthal fossil (La Ferrassie 1; left) and of a modern human (right). One of the
features that distinguishes modern humans from Neanderthals is a globular shape of the braincase. ​The cranium
was cut open virtually to reveal the inside of the braincase [Credit: © Philipp Gunz]

Modern human skulls have a unique ‘globular’ (round) shape. Our closest cousins, the long extinct Neanderthals, had the elongated skulls that are typical of most primates. This striking shape difference is suspected to reflect evolutionary changes in the relative sizes of structures of the human brain, perhaps even in the ways that key brain areas are connected to each other. However, brain tissue doesn’t itself fossilize, so the underlying biological explanation has remained elusive.
An international research team, led by paleoanthropologist Philipp Gunz (MPI, Leipzig) and geneticists Simon Fisher and Amanda Tilot (MPI, Nijmegen), developed a new strategy to investigate this question. The team combined analysis of fossil skulls, ancient genome sequence data and brain imaging.

“Our aim was to identify potential candidate genes and biological pathways that are related to brain globularity,” says Tilot. To focus their search, they took advantage of the fact that living humans with European ancestry carry rare fragments of Neanderthal DNA buried in their genomes, as a result of interbreeding between Neanderthals and the ancestors of modern Europeans. Different people carry different fragments, which are scattered through the genome.

Neanderthal genes influence brain development of modern humans
The authors combine paleoanthropology, archaic genomics, neuroimaging and gene expression to study biological
foundations of the characteristic modern human endocranial shape. Shown here are the coordinate measurements
used to capture endocranial shape from magnetic resonance images of several thousand modern humans
[Credit: © Philipp Gunz]

The researchers first used computed tomographic scans of fossil Neanderthal skulls and skulls of modern humans to make endocasts—virtual imprints of the interior of the braincase. They then developed a single measure of globularity, based on the differences in skull shape between humans and Neanderthals. Next, the scientists teamed up with colleagues at the Radboud University, the University of Greifswald and UC Irvine, to determine the degree of globularity of thousands of healthy present-day humans, using data from magnetic resonance imaging.
Although modern human brain and skull shapes are all clearly distinct from those of Neanderthals, the scientists still found considerable differences in globularity among the participants. Finally, the researchers studied the genomes of around 4,500 of the participants to identify the fragments of Neanderthal DNA that each person carried. Would any of these Neanderthal DNA fragments influence brain globularity in their living human sample?

The team found Neanderthal DNA fragments on chromosomes 1 and 18 that were associated with less globular (more elongated) brains. These fragments were associated with altered activity of two genes, UBR4 and PHLPP1, which are already known to play roles in important aspects of brain development (neurogenesis and myelination respectively). The strongest evidence for effects of these Neanderthal DNA fragments on gene activity were in the putamen (in the basal ganglia) and the cerebellum.

Neanderthal genes influence brain development of modern humans
Computed tomographicscan of the Neanderthal fossil from La Chapelle-aux-Saints (left) with a typical elongated
endocranial imprint (red) and of a modern human (right) showing the characteristic globular endocranial shape (blue).
 Arrows highlight the enlarged posterior cranial fossa (housing the cerebellum) as well as bulging of parietal bones
in modern humans compared to Neanderthals [Credit: © Philipp Gunz]

“The potential for links between evolutionary changes in brain globularity and mechanisms affecting the basal ganglia and cerebellum is intriguing,” says Gunz. Both structures receive direct input from the motor cortex and are involved in the preparation, learning, and coordination of movements. The basal ganglia also contribute to cognitive functions such as memory, attention, planning, skill learning, and potentially speech and language evolution.
The authors stress that recent archaeological evidence has documented sophisticated symbolic behaviours in Neanderthals that had previously been attributed exclusively to modern humans, such as the enigmatic structure built deep inside Bruniquel cave, and Neanderthal cave-art from Iberia. As Gunz notes, “The focus of our study is on understanding the unusual brain shape of modern humans. These results cannot be used to make inferences about what Neanderthals could or could not do.”

“The effects of carrying these rare Neanderthal DNA fragments are really subtle, but detectable due to the large sample size,” explains Fisher, adding “This is only our first glimpse of the molecular underpinnings of globularity. Like other aspects of brain structure, globularity is a trait that is likely to be influenced by the combined effects of many different genetic variants.”

This animation shows computed tomographic (CT) scans of a Neandertal cranium (left) 

and a recent modern human (right) [Credit: Philipp Gunz]

According to the research team, this discovery generates hypotheses that can be tested with new experiments, for example using human neuronal tissue that can be grown in the laboratory. Gunz and Fisher are now scaling-up the approach for investigations in larger samples such as the UK Biobank. They anticipate that future genome-wide screening studies will reveal additional genes associated with globularity, as well as indicate how this fascinating trait is linked to other aspects of human biology.

Source: Max Planck Society [December 13, 2018]

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Research team discovers oldest known plant virus at ancient settlement

Researchers studying ancient corncobs found at a Native American archaeological site have recovered a 1,000-year-old virus, the oldest plant virus ever reported.

Research team discovers oldest known plant virus at ancient settlement
Examining 1,000-year-old corn cobs from an ancient ruin in Arizona, researchers found a previously
unknown virus – the oldest plant virus ever reported [Credit: Roossinck Laboratory, Penn State]

Only a few RNA viruses had been discovered previously from archaeological samples, the oldest dating from about 750 years ago. The new discovery came as the research team examined ancient plant material from Antelope House, an Ancestral Puebloan ruin located at Canyon de Chelly National Monument, Arizona.

The Ancestral Puebloans who lived in the canyon planted crops such as maize, beans and squash. During the excavation of Antelope House by the National Park Service in the 1970s, more than two tons of plant refuse, in highly recognizable form, were recovered.

“It’s clear from these remains that maize was a major food source for the inhabitants,” said lead researcher Marilyn Roossinck, professor of plant pathology and environmental microbiology, College of Agricultural Sciences, Penn State. “The maize remnants recovered at Antelope House consisted of cobs, ears with kernels, individual kernels, husks, leaves, shanks, stem portions and tassels.”

Using carbon 14 dating, researchers confirmed that the age of the ancient samples was about 1,000 years old. While analyzing cobs, the scientists isolated three nearly complete genomes of a previously unknown virus of the family Chrysoviridae, which infect plants and fungi.

Research team discovers oldest known plant virus at ancient settlement
Ancient inhabitants of the Antelope House ruin, in Arizona’s Canyon de Chelly National Monument,
grew crops such as maize, beans and squash [Credit: National Parks Service]

The researchers, who report their findings in the current issue of the Journal of Virology, noted that chrysoviruses are persistent plant viruses that are transmitted from generation to generation through seeds and can remain in their hosts for very long time periods. Persistent viruses typically do not cause disease and rarely are detected. This is the first chrysovirus described from maize, Roossinck noted.

“When we analyzed modern corn samples, we found the same chrysovirus with only about 3 percent divergence from the ancient samples,” she said. “Most RNA viruses, with short generation times and error-prone replication, evolve rapidly. However, persistent viruses have very stable genomes.”

Roossinck said the most interesting aspect of the findings for the team is that the virus has been maintained in corn for so long.

“That implies that the virus might confer some potential benefit to the plant, but we haven’t shown that yet,” she said.

Source: Penn State [December 13, 2018]

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