THE 'CIAMPATE DEL DIAVOLO', HOMO HEIDELBERGENSIS

Today, The Grandma has received interesting news from Joseph de Ca'th Lon, one of her closest friends.

 

Joseph is in Naples visiting the Ciampate del Diavolo, where an article in Nature identifies fossilized hominid footprints preserved in pyroclastic flow deposits that dated to around 350,000 years ago on a day like today in 2003.

The Ciampate del Diavolo, in Neapolitan Devil's Footprints or Devil's Trails, is a locality near the extinct Roccamonfina volcano in northern Campania, Italy.

It is named after fossilized hominid footprints preserved in pyroclastic flow deposits that have been dated to around 350,000 years ago.

They have been attributed to bipedal hominids, possibly Homo heidelbergensis, which is known to have inhabited the region at the time.

The footprints comprise three sets of tracks indicating that three hominids made their way down a steep slope on the flank of the volcano, away from the crater. The tracks were preserved under a layer of volcanic ash and were revealed by erosion, probably in the late 18th to early 19th century. Local people attributed the prints to the Devil as they regarded him as the only being capable of walking on lava without harm.

They were identified as hominid footprints after archaeologists examined them in 2002 and are the second oldest set of hominid footprints known outside Africa, after the Happisburgh footprints.

The area in which the tracks appear is an eroded layer of rock covering about 2,000 m², tilted at an angle of about 45°, in a forest on the side of the volcano. The footprints consist of three sets of tracks which descend a steep slope created by a pyroclastic flow.

More information: Discover Campania

The first, identified as Trackway A, measures 13.4 metres and consists of 27 prints from left and right feet descending 4.26 metres vertically along a Z-shaped course. It testifies to a careful descent down a steep and probably unstable slope. 

Trackway B is 8.6 metres long and descends 2.91 metres vertically along a single curved route. Less care was taken with this part of the descent, as slips and irregularities indicating stumbles are visible. Finally, the less well-preserved 

Trackway C measures 9.98 metres along a single straight line which descends 2.56 metres vertically.

Occasional handprints are visible where the track-maker sought support on the steep slope, and a couple of animal paw marks made by a big dog or wolf are also visible.

Until the discovery of the Happisburgh footprints in England in 2013, they were the oldest known hominid footprints outside Africa. The tracks were originally dated to between 385,000 and 325,000 years ago, but subsequent studies using argon-argon dating placed the date more precisely as around 349-350,000 years ago.

The pyroclastic deposits in which the footprints were imprinted were laid down around 349,000 years ago (±3,000 years), while the layer of volcanic ash which subsequently covered and preserved them was deposited around 350,000 years ago (±3,000 years). The footprints are thought to have been exposed by erosion caused by heavy precipitation and landslides in the early 19th century, when the name Ciampate del Diavolo was first recorded.

The track-makers are estimated to have been about 1.56 metres tall and to have been travelling at a speed of 1.09 metres per second. Based on the age of the tracks, they have been tentatively ascribed to the hominid Homo heidelbergensis, a probable ancestor of the Neanderthals. As the tracks point away from the volcano's crater, it is possible that they were made while the track-makers were trying to escape an eruption. There was certainly an eruption following the track-makers' passage, as the tracks were buried under a subsequently erupted layer of volcanic ash which preserved them to the present day.

More information: Science Alert

Based on the small stature of the individuals, it has been suggested that the prints were made by children.

The tracks were known locally for many years, as they are situated near a trail that was established in the 18th century between the villages of Tuoro/Foresta and Piccilli. Local people attributed them to the Devil, the only being considered capable of walking on lava without burning his feet, but despite this the site was not considered cursed or threatening.

In 1986 a writer suggested that the footprints might have been created in historic times by a human. It was not until 2002 that they were first brought to scientific attention by two amateur archaeologists who noticed them and informed archaeologists at the University of Padua.

A cattle path through the forest formerly crossed the fossil tracks and caused accelerated erosion at that point, but since 2001 the vegetation around the tracks has been cleared away and the exposed rock protected by fencing. The tracks were initially thought to have been made by prehistoric elephants but when Paolo Mietto and two other researchers from the University of Padua investigated them, they were surprised to find that the tracks were of hominid origin.

It is very rare to find preserved hominid footprints in open-air environments, where they are vulnerable to erosion; most examples are found in enclosed and thus better protected environments such as caves.

More information: Forbes

One of the few things that can be said
for certain about Europe's prehistoric peoples
is that they all came from somewhere else.

Norman Davies

THE HUMAN GENOME, NUCLEIC ACID SEQUENCES (DNA)

Today, The Grandma has received the wonderful visit of one of her best friends, Joseph de Ca'th Lon. They have been talking about the human genome.

 

The first draft of the complete human genome was published in Nature on a day like today in 2001 and Joseph has explained her lots of things about it.

 

The human genome is a complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria.

These are usually treated separately as the nuclear genome, and the mitochondrial genome.

Human genomes include both protein-coding DNA genes and noncoding DNA.

Haploid human genomes, which are contained in germ cells (the egg and sperm gamete cells created in the meiosis phase of sexual reproduction before fertilization creates a zygote) consist of three billion DNA base pairs, while diploid genomes (found in somatic cells) have twice the DNA content.

While there are significant differences among the genomes of human individuals (on the order of 0.1% due to single-nucleotide variants and 0.6% when considering indels), these are considerably smaller than the differences between humans and their closest living relatives, the bonobos and chimpanzees (~1.1% fixed single-nucleotide variants and 4% when including indels).

The first human genome sequences were published in nearly complete draft form in February 2001 by the Human Genome Project and Celera Corporation.

More information: Human Genoma Project Information Archive

Completion of the Human Genome Project's sequencing effort was announced in 2004 with the publication of a draft genome sequence, leaving just 341 gaps in the sequence, representing highly-repetitive and other DNA that could not be sequenced with the technology available at the time.

The human genome was the first of all vertebrates to be sequenced to such near-completion, and as of 2018, the diploid genomes of over a million individual humans had been determined using next-generation sequencing. These data are used worldwide in biomedical science, anthropology, forensics and other branches of science.

Such genomic studies have led to advances in the diagnosis and treatment of diseases, and to new insights in many fields of biology, including human evolution.

Although the sequence of the human genome has been (almost) completely determined by DNA sequencing, it is not yet fully understood. Most (though probably not all) genes have been identified by a combination of high throughput experimental and bioinformatics approaches, yet much work still needs to be done to further elucidate the biological functions of their protein and RNA products. 

Recent results suggest that most of the vast quantities of non-coding DNA within the genome have associated biochemical activities, including regulation of gene expression, organization of chromosome architecture, and signals controlling epigenetic inheritance.

Prior to the acquisition of the full genome sequence, estimates of the number of human genes ranged from 50,000 to 140,000, with occasional vagueness about whether these estimates included non-protein coding genes.

More information: DDW

As genome sequence quality and the methods for identifying protein-coding genes improved, the count of recognized protein-coding genes dropped to 19,000-20,000. However, a fuller understanding of the role played by sequences that do not encode proteins, but instead express regulatory RNA, has raised the total number of genes to at least 46,831, plus another 2300 micro-RNA genes.

By 2012, functional DNA elements that encode neither RNA nor proteins have been noted and another 10% equivalent of human genome was found in a recent (2018) population survey. Protein-coding sequences account for only a very small fraction of the genome (approximately 1.5%), and the rest is associated with non-coding RNA genes, regulatory DNA sequences, LINEs, SINEs, introns, and sequences for which as yet no function has been determined.

In June 2016, scientists formally announced HGP-Write, a plan to synthesize the human genome.

Although the 'completion' of the human genome project was announced in 2001, there remained hundreds of gaps, with about 5–10% of the total sequence remaining undetermined.

The missing genetic information was mostly in repetitive heterochromatic regions and near the centromeres and telomeres, but also some gene-encoding euchromatic regions. There remained 160 euchromatic gaps in 2015 when the sequences spanning another 50 formerly-unsequenced regions were determined. 

Only in 2020 was the first truly complete telomere-to-telomere sequence of a human chromosome determined, namely of the X chromosome.

More information: The New York Times

Even if we never cure a single disease,
the Human Genome Project and other ventures
will have been worth it.

Sam Kean

THE NEANDERTHAL GENOME & THE MODERN HUMANS

A modern human and a Neanderthal one

When modern humans migrated out of Africa some 60,000 years ago, they found the Eurasian continent already inhabited by brawny, big-browed Neanderthals. We know that at least some encounters between the two kinds of human produced offspring, because the genomes of people living outside Africa today are composed of some 1 to 4 percent Neanderthal DNA.

Some parts of non-African genomes are totally devoid of Neanderthal DNA, but other regions abound with it, including those containing genes that affect our skin and hair. This hints that the Neanderthal gene versions conferred some benefit, and were kept during evolution.

The fact that Neanderthal DNA is totally absent from other stretches of the modern non-African genome suggests that their versions of the genes in these regions would have caused problems in modern humans, and were weeded out by natural selection.

More information: Science

A Neanderthal and his skull

In the Nature study, Sriram Sankararaman and David Reich of Harvard Medical School used the previously sequenced Neanderthal genome to screen 1,004 modern genomes for sequences with distinctive Neanderthal features.

If a fragment of DNA is shared by Neanderthals and non-Africans, but not Africans or other primates, it is likely to be a Neanderthal heirloom. Also, Neanderthal sequences are typically inherited in large batches, since they were imported into the modern human genome relatively recently and have not had time to break apart.

In the Science study, Akey and Benjamin Vernot, both of the University of Washington in Seattle, used similar statistical features to search for Neanderthal DNA in the genomes of 665 living people—but they initially did so without the Neanderthal genome as a reference. They still managed to identify fragments that collectively amount to 20 percent of the full Neanderthal genome.

More information: Nature

Neanderthal Influence on Skin, Hair, Common Diseases

Despite their different approaches, both teams converged on similar results. They both found that genes involved in making keratin—the protein found in our skin, hair, and nails—are especially rich in Neanderthal DNA.

For example, the Neanderthal version of the skin gene POU2F3 is found in around 66 percent of East Asians, while the Neanderthal version of BNC2, which affects skin color, among other traits, is found in 70 percent of Europeans.

Comparison: Modern Humans and Neanderthals

The Neanderthal version of these genes may have helped our ancestors thrive in parts of the world that they were not familiar with but that Neanderthals had already adapted to. 

Neanderthals had been in these environments for hundreds or thousands of years, says Sankararaman. As modern human ancestors moved into these areas, one way to quickly adapt would be to get genes from the Neanderthals.

Unfortunately, skin and hair do so many things that it's hard to speculate on what specifically that adaptive trait was, says Akey.

Sankararaman also found Neanderthal variants in genes that affect the risk of several diseases, including lupus, biliary cirrhosis, Crohn's disease, and type 2 diabetes. The significance of these sequences is even less clear.

More information: New Historian

Both teams found that non-African genomes have large continuous deserts that are totally devoid of Neanderthal DNA. These regions include genes such as FOXP2, which is involved in motor coordination and could play an important role in human language and speech.

The Neanderthal-poor deserts are especially big in the X chromosome, and include genes that are specifically activated in testes. This hints that some Neanderthal genes may have reduced the fertility of male modern humans and were eventually lost. However, Hawks cautions that this probably happened over hundreds of generations—it was very unlikely that the sons of Neanderthals and modern humans were obviously infertile.

DNA Hints at Other Mystery Humans

A Neanderthal man

Both teams are now planning to apply their methods to other hominids like the Denisovans—an enigmatic group whose presence in Asia some 40,000 years ago is known just from DNA from a finger bone and some teeth found in a single cave in Russia.

And Akey's work shows that it may even be possible to partially reconstruct the genomes of unknown groups of ancient humans without any prehistoric DNA samples.

It is becoming increasingly clear that the Pleistocene was awash with many different groups of early humans, hooking up with each other to various degrees. Recent studies, for instance, have found tantalizing hints of unknown groups from Asia and Africa that left genes in Denisovans and modern humans, respectively. Akey's method could give us our first glimpse at these mystery humans.

If there is no fossil evidence and potentially never will be, this will be the only way of finding out about groups that were important in human history, he added.

If we turn to palaeontology to tell us about our biological evolution it is to prehistory that we look for evidence of the evolution of specifically human patterns of behaviour. 

John G. D. Clark

CHRISTMAS TREE, DECORATIONS & QUEEN VICTORIA

Christmas

The Christmas tree tradition has got a German origin. In 1832, Queen Victoria, when she was still a teenager, in her journal for Christmas Eve wrote: 

"After dinner... we then went into the drawing-room near the dining-room... There were two large round tables on which were placed two trees hung with lights and sugar ornaments. All the presents being placed round the trees..."

Nowadays, the tradition continues but, fortunately, the natural trees are being replaced by the plastic ones, in an attempt of protecting and conserving our Nature and Environment.

Have a nice day!