Unraveling Ancient Skins: Pigmentation Insights from Ancient DNA

This study delves into the fascinating world of ancient genetics, specifically focusing on the skin, hair, and eye colour of early Europeans determined through their DNA. The team, led by researchers like Silvia Perretti and Guido Barbujani, uses a statistical method known as genotype likelihood to analyze ancient DNA samples.

• The first light-skinned individuals appeared in the Mesolithic period (14,000-4,000 years ago).
• During the Bronze Age (7,000-3,000 years ago), the proportion of dark-skinned people was still significant.
• During the Iron Age (3,000-1,700 years ago), light skin color began to dominate.

The real turning point was the spread of Neolithic farmers, who arrived from Anatolia 10,000 years ago. These early farmers carried genes for lighter skin, which probably gave them an evolutionary advantage in the less sunny climate of Europe. Their genes spread over time, but the process was slow and uneven. 
Traditionally, lighter skin has been thought to have evolved to enhance vitamin D production, but new evidence suggests that diet may have played a key role. As humans evolved from small nomadic groups to larger, agricultural communities, their diets changed. They relied less on wild game, which was rich in vitamin D, and more on cultivated plants, which lacked the vitamin. This change, along with the need to absorb more sunlight in northern latitudes, may have led to the development of lighter skin."

https://www.origo.hu/tudomany/2025/02/bor-sotet-volt-europaban


The actual paper:

Abstract:

Light eyes, hair and skins probably evolved several times as Homo sapiens dispersed from Africa. In areas with lower UV radiation, light pigmentation alleles increased in frequency because of their adaptive advantage and of other contingent factors such as migration and drift. However, the tempo and mode of their spread is not known. Phenotypic inference from ancient DNA is complicated, both because these traits are polygenic, and because of low sequence depth. We evaluated the effects of the latter by randomly removing reads in two high-coverage ancient samples, the Paleolithic Ust’-Ishim from Russia and the Mesolithic SF12 from Sweden. We could thus compare three approaches to pigmentation inference, concluding that, for suboptimal levels of coverage (<8x),  a probabilistic method estimating genotype likelihoods leads to the most robust predictions. We then applied that protocol to 348 ancient genomes from Eurasia, describing how skin, eye and hair color evolved over the past 45,000 years. The shift towards lighter pigmentations turned out to be all but linear in time and place, and slower than expected, with half of the individuals showing dark or intermediate skin colors well into the Copper and Iron ages. We also observed a peak of light eye pigmentation in Mesolithic times, and an accelerated change during the spread of Neolithic farmers over Western Eurasia, although localized processes of gene flow and admixture, or lack thereof, also played a significant role.

Inference of human pigmentation from ancient DNA by genotype likelihood Silvia Perretti, Maria Teresa Vizzari, Patrícia Santos, Enrico Tassani, Andrea Benazzo, Silvia Ghirotto, Guido Barbujani bioRxiv 2025.01.29.635495; doi: https://doi.org/10.1101/2025.01.29.635495 

This is a preprint and has not been certified by peer review

Water swollen wooden wedges for splitting stone, a myth?

We have all heard of splitting stones by inserting dry wooden wedges into cracks and then soaking them. But I can't find any examples of it actually being tried. Literature searches give me these results:

"The use of wooden wedges and hydraulic expansion to split stone occupies a nebulous position between historical anecdote and mechanical plausibility. While physics principles and traditional narratives support its feasibility, the absence of contemporary demonstrations or archaeological incontrovertible evidence leaves the method in the realm of theoretical speculation."

"No experimental or quantitative data exists for the specific use of water-swollen wooden wedges in splitting stone.
The hypothesis that water-swollen wooden wedges were used as a stone-splitting technique is archaeologically plausible but lacks modern experimental support."

"while the theoretical framework and related experimental studies provide a basis for understanding the mechanics of wetting and splitting, the absence of specific practical demonstrations leaves a gap in empirical validation of this method."

So is it a myth or was it actually used? 

Roger Rowell claims to have seen the technique used in Egyptian quarries:

On a trip to Egypt in 2001, the author saw the evidence first hand. On the edge of a shear granite cliff, holes about 15 cm long, 5 cm wide and 10 cm deep had been chiseled into the rock. Dry wooden wedges the size of the cavities were driven into these holes. Water was then poured onto the dry wood and allowed to swell. The swelling pressure caused the granite to split down the chain of holes resulting in a giant obelisk or other large building blocks. 

Rowell, Roger. (2012). 4 Moisture Properties. Handbook of Wood Chemistry and Wood Composites. 10.1201/b12487-7. 

Further citations are provided in: Nishiyama, Yoshiharu. (2023). Thermodynamics of the swelling work of wood and non-ionic polysaccharides: A revisit. Carbohydrate Polymers. 320. 121227. 10.1016/j.carbpol.2023.121227. 

A quite demonstrative example is the splitting of granite rocks by the swelling power of wooden wedges inserted in small chiseled holes as was witnessed by Rowell (2012) for which many authors assert the use of such methods in ancient Egypt (Eder, Schäffner, Burgert, & Fratzl, 2020;Katz, 1917), though the historical veracity seems controversial (Harrell & Storemyr, 2009).

Harrell & Storemyr, 2009 are quite clear:

A fiction often repeated in the popular archeological literature is that the wedge holes were cut for wooden wedges which, when wetted, would expand and so split the rock. In reality, this cannot work for the sizes, shapes, spacings, and often inclined orientations of wedge holes found in ancient hardstone quarries. Wooden wedges have been successfully employed in some modern hardstone quarries, but these require different kinds of wedge holes. (Harrell & Storemyr, 2009)

El-Sehily, B.M.. (2016). Fracture Mechanics in Ancient Egypt. Procedia Structural Integrity. 2. 2921-2928. 10.1016/j.prostr.2016.06.365.  provides details of a trial using swollen wooden wedges, to crack the rock blows were then applied to the stressed rock.

The Archive Excavation of the Altar Stone

In 1958 Richard Atkinson excavated around the Altar Stone at Stonehenge. Photographs of the excavation held in the Historic England Archive were examined by Tim Daw on 28th January 2025 with the greatly appreciated assistance of Simon Banton. Many of the photos were not recorded as being of the Altar Stone and were found only by careful study of entire archive. The following illustrate previously unrecorded features of the Altar Stone. The photos are labelled with the Historic England archive number, and present archive description, and the direction of the shot is illustrated on the annotated plan below.

They have been digitised by Historic England for Tim Daw. They are all copyright Historic England and reproduced here under Permission No: 10238. Digital copies will be made available on the Historic England archive website in due course. The photos here have been reduced in size or are the web versions to comply with the reproduction licence. Click them to embiggen to the size allowed, the originals are three time larger.   

He also lifted Stone 55B to examine the underside of 55B – the very brief description of the excavation is in his book “Stonehenge, 1979 revised edition” and does not include a description of the lifting of 55b. The photos in the archive seem to be the only record revealing its finely worked surface. 

The photo locations based on Atkinson’s plan in Cleal et al, rotated for convenience.



P51196 (1958 Excavation Near Alter Stone (St.80))
The excavated North East face showing the break and loose fragments.

P51908 (1958 Excavation Of Altar Stone,Stone 80) Looking South West at excavated Altar Stone. P51909 is very similar but not digitised.

P50361 (Excavated Unidentified Stone) The South East end from the North East 

Click photos to embiggen to the size allowed, the originals are three time larger.    

P50359 (Excavated Unidentified Stone) Vertical of South East end

P50102 (1958 Excavation Of Altar Stone. S.E. End, View S.W.) South East end from the South West showing the graffito noted as “IB” by Atkinson on his plan. Stone 55b is to the left.

Simon Banton notes that a similar engraving, “FB”, is on Stone 62. The crossed I or F is also similar to the symbol on the WREN graffito on Stone 52.

 

Photos from Stones of Stonehenge - Simon Banton

P50002 (Unidentified Stone, Carved Initials "Id”) South East end from South showing “IB” engraving

P50005 (2 Unidentified Stones In Excavation) The South West side of the Altar Stone under 55b taken at night for lighting purposes. The stone extends from the break in the foreground to the baulk under 156. 

P50009  (2 Unidentified Stones In Excavation) is a similar photo revealing the fine working of the stone. The scratches at the top of the stone are similar to the ones on the middle section, see below, but from these photos it is uncertain what they are.

P51808 (1958 Excavation Of Alter Stone, Stone 80) Altar Stone – The middle section of the top surface between 55b, top, and 156, bottom,



P50107 (Surface Of Altar Stone From North East) Middle Section of South West side of the Altar Stone showing engraved lines, taken from South West . 

P50106 is similar. These scratches have obvious similarity to other neolithic stone markings. The vertical line is thought to be a quartz vein in the stone.

 

P50811 (1958 Excavation Of Alter Stone, Stone 80) Altar Stone North West end from above, standing on 156.




P51805 (1958 Excavation Of Alter Stone,Stone 80) North West end of the Altar Stone under 156.

P51874 (1958 Lifting Of Stone 55B) – The best photos of the top of the Altar Stone, it doesn’t seem to have been photographed when 55b was lifted.

P51873 (1958 Lifting Of Stone 55B) looking South East with the Altar Stone exposed. The methods used for the lifting of the stone might be thought not to follow present day best practice.

P50371 (Atkinson Looking At Unidentified Stone With Cable) Richard Atkinson underneath 55b looking South West, he is lying against 156 and 55a is on the ground to the left protected by the wooden post.  

Click photos to embiggen to the size allowed, the originals are three time larger.    

The source of the quartz at Newgrange

I gather that misinformation about the stones of Newgrange is being strewn across the interweb.

So quickly here is the present state of knowledge:

"Newgrange, a Neolithic monument built around 3200 BCE,in Ireland's Boyne Valley, is renowned for its intricate architecture and the variety of stones used in its construction.  The stones that make up Newgrange were sourced from diverse locations, reflecting the builders' ability to transport and utilize materials from across the region.

The Newgrange mound is primarily composed of thousands of water-rolled stones gathered from the nearby River Boyne. These stones, weighing approximately 200,000 tonnes, form the bulk of the cairn. The inner passageway and outer kerbstones are made of greywacke, a type of stone that was likely collected from the rocky beach at Clogherhead, County Louth, about 20 km to the northeast.

The exterior of Newgrange features a striking array of decorative stones, including:

White Quartz Cobbles: These were transported from the Wicklow Mountains, approximately 50 km to the south. The quartz stones were used to create a facade that has been reconstructed in modern times.

Dark Speckled Granodiorite Cobbles: Originating from the Mourne Mountains, about 50 km to the north, these stones add a distinctive element to the monument's design.

Dark Gabbro Cobbles: Sourced from the Cooley Mountains, these stones contribute to the complex's visual appeal.

Inside the chambers, granite basins were used, which were brought from the Mournes. These basins are significant not only for their material but also for their role in the structure's function, possibly as repositories for the remains of the dead." 

From: https://www.perplexity.ai/search/write-a-blog-post-with-referen-53n66lYrS06qukqxIX0kqQ#0

Click to enlarge - from: Notes on Some Non-Local Cobbles at the Entrances to the Passage-Graves at Newgrange and Knowth, County Meath Frank Mitchell The Journal of the Royal Society of Antiquaries of Ireland, Vol. 122 (1992), pp. 128-145 (18 pages) https://www.jstor.org/stable/25509025 

From http://iqua.ie/wp-content/uploads/2019/12/Newsletter-NS-No-28_grey.pdf

And supporting this there is, for the academics with access, the magisterial: 

Meighan, I.G., Simpston, D.D.A., Hartwell, B.N., Fallick, A.E. and Kennan, P.S. (2003) Sourcing the quartz at Newgrange, Bru na Boinne, Ireland. In: Burenhult, G. and Westergaard, S. (eds.) Stones and Bones: Formal Disposal of the Dead in Atlantic Europe During the Mesolithic-Neolithic Interface 6000-3000 BC: Archaeological Conference in Honour of the Late Professor Michael J. O'Kelly. Series: BAR international series (1201). Archaeopress: Oxford, UK, pp. 247-251. ISBN 9781841715667

There is no evidence to show that any quartz stones were brought onto the site during the reconstruction. O'Kelly excavated the "numerous angular fragments" he used from in front of the monument. Whether his reconstruction is in any way accurate is another matter. 

O’Kelly, M.J. (1979) ‘The restoration of Newgrange’, Antiquity, 53(209), pp. 205–210. doi:10.1017/S0003598X00042538.

The Combined Viewshed of the Tor and Cuckoo Stones.

 The new paper on the Tor and Cuckoo Stone* posits that: "The intervisibility of the two stones is likely to have been an essential feature of their locations, near the boundaries of their respective overlapping viewsheds,... the DTM indicates that a transect drawn between the two stones  passes close to the apex of a meander in the River Avon at a point where it is approximately equidistant from each stone and potentially intervisible, both from and towards both stones.

The paper has shows their individual viewsheds but not them combined. Simply overlaying the two figures and tweaking the colours gives the combined viewshed. 

Click to enlarge - all rights remain with the original paper

The mustard colour shows where both stones would be visible from, I thought they might have acted as pillars visible either side from the route through the landscape but that doesn't seem to be. But the apex of the river meander could be important. More to ponder on.

*HARDING, P. et al. (2025) ‘Earliest Movement of Sarsen Into the Stonehenge Landscape: New Insights from Geochemical and Visibility Analysis of the Cuckoo Stone and Tor Stone’, Proceedings of the Prehistoric Society, pp. 1–23. doi:10.1017/ppr.2024.13.

None of the Stonehenge Stones are Local

The new paper on the Cuckoo and Tor stones (*) posits that they are not local to Salisbury Plain and were brought from West Woods. It goes further and claims that no large numbers of large sarsens with a chemistry the same as those at West Woods are likely to have originated near Stonehenge.

This is surprising. They debate the obvious question here:

https://www.cambridge.org/core/journals/proceedings-of-the-prehistoric-society/article/earliest-movement-of-sarsen-into-the-stonehenge-landscape-new-insights-from-geochemical-and-visibility-analysis-of-the-cuckoo-stone-and-tor-stone/C7C6D363A6E59D0BBF5C3158077ABB24#s4

Geological implications

Our inference that the Cuckoo Stone and Tor Stone probably originated in the West Woods area directly challenges the suggestion made by Richards (Reference Richards and Parker2020) that both stones were either already situated at, or close to, their source locations when they were monumentalised. There is, however, a potential counter argument that would support Richards’ view: rather than the two stones being moved from West Woods, could it be that large sarsen boulders with a geochemistry similar to those at West Woods were already present in the Stonehenge landscape near the sites where the two stones were raised?

Their answer is no and I find their reasoning compelling.

* HARDING, P. et al. (2025) ‘Earliest Movement of Sarsen Into the Stonehenge Landscape: New Insights from Geochemical and Visibility Analysis of the Cuckoo Stone and Tor Stone’, Proceedings of the Prehistoric Society, pp. 1–23. doi:10.1017/ppr.2024.13.

Earliest Movement of Sarsen Into the Stonehenge Landscape:

Earliest Movement of Sarsen Into the Stonehenge Landscape: New Insights from Geochemical and Visibility Analysis of the Cuckoo Stone and Tor Stone

Abstract: This paper presents the results of new research on two sarsen stones, known as the Cuckoo Stone and Tor Stone, both former standing stones that lie on opposite banks of the River Avon and straddle the eastern border of the Stonehenge and Avebury World Heritage Site. Geochemical analysis indicates that both stones were probably transported to their present site from West Woods on the Marlborough Downs in north Wiltshire, a source that likely also supplied the large sarsen monoliths at Stonehenge. The paper examines the geological conditions necessary for the formation of sarsen across the site of the present-day Salisbury Plain to address the apparent absence of natural sarsen in the area. The results are integrated with those of archaeological fieldwork from nearby contemporaneous sites to suggest that the Cuckoo Stone and Tor Stone were probably introduced into the Stonehenge landscape in the early part of the Late Neolithic period, ie, contemporary with Phase 1 of Stonehenge and some 400–500 years before the construction of the principal sarsen settings at the monument. Visibility analysis indicates that the two stones were probably intervisible and likely to have formed part of a planned landscape and were positioned to create a formal portal to the Stonehenge area on either bank of the River Avon.

HARDING, P. et al. (2025) ‘Earliest Movement of Sarsen Into the Stonehenge Landscape: New Insights from Geochemical and Visibility Analysis of the Cuckoo Stone and Tor Stone’, Proceedings of the Prehistoric Society, pp. 1–23. doi:10.1017/ppr.2024.13.