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Category Archives: Epipaleolithic

Fu 2013: new ancient mtDNA sequences and "molecular clock" madness

It took me quite a while to get time to look at this study in some depth and when I finally did I must say I was rather disappointed. In any case the popular demand makes necessary to discuss it.
Qiaomei Fu et al., A Revised Timescale for Human Evolution Based on Ancient Mitochondrial Genomes. Current Biology 2013. Pay per viewLINK [doi:10.1016/j.cub.2013.02.044]
The study has two aspects: one, of great interest, which is the sequencing of a number of ancient remains, the other a complex and quite poorly explained and rendered speculation on how these sequences could be used to produce a refined molecular clock. 
Ancient mtDNA sequences
Most of the sequences used by Fu et al. in their molecular clock speculations are new and that part is very interesting:

I have highlighted in lime green the new sequences, otherwise also noted by the marker b. It is of note that the “Crô-Magnon 1” sequence produced a C14 age of just a few centuries, being therefore removed from the collection. Other Crô-Magnon 1 remains produced no useful data. 
The authors also decided to discard as possibly contaminated the UP sequence  from Pagicci Str. 4b. I have highlighted in red why they decided to do so: because the C→T misincorporation rate, characteristic of ancient remains, is too low, what makes contamination at least a serious probability. 
So we have as new data for the Upper Paleolithic landscape in Europe that the people of Dolni Vestonice carried lineages U* (found also in Swabian Magdalenian) and U8, in the line of haplogroups K, U8a (Basque) and U8b (Eastern Mediterranean). Also some late UP and Epipaleolithic sequences from Oberkassel (Low Rhineland, Germany), Loschbour (Luxemburg) and Continenza (Abruzzo, Italy) are U5b variants, consistent with other findings from various parts of Europe. In Paglicci (Apulia, Italy), another sequence yielded U2’3’4’7’8’9, surely an extinct variant of the ancestor of U8 and U2 (among other lineages). No radiocarbon date is available for any of the Italian remains.
In East Asia, Boschan, with B4c1a, provides one of the first Epipaleolithic sequences for the region. 

Molecular clock madness

The authors seem to intend, or so declare, to refine the molecular clock estimates by means of using these sequences as intermediate calibration references. Here I get the first big question: with all the literature on ancient DNA, why only these sequences? No idea.
Then the contradictions arise. I believe that I have synthesized the most obvious ones in the following marginal annotations (in red) to their molecular clock estimates:

Furthermore, the authors claim in the text that U5 is the oldest branch to diverge from U, however their TRMCA figure is of only 34.4 Ka BP (coding region), while Kostenki 14 has an age of 38 Ka BP and already carried U2, what really makes this claim extremely unlikely: U2 and its ancestor U2’3’4’7’8’9 should be considered the oldest U sublineage. 
I do not understand either why they force age estimates for many lineages for which they have no working aDNA references and instead desist of estimating the age of lineages for which they have several calibration points, like U2’3’4’7’8’9 or B4’5 (aka B). 
In brief: the claims of this paper on molecular-clock-o-logy are ill-explained, confusing, incoherent… a total mess. The raw data on ancient mtDNA is however good looking and of doubtless interest.
 

Rock art from Baja California dates to c. 9,000 years ago, maybe even older

Catalan researchers from the IPHES have been studying the impressive rock art of the caves of Baja California Sur (Mexico) and concluded that some of the art is from c. 8-9,000 years ago. However contextual dates are sometimes older, of c. 10-11,000 years ago. 

Source: El Universal[es], which has many more photos.
For decades it was believed, following the pioneer work of Clement Meighan, that the art was from the 13th century CE. However in the 1980s the more in-depth research by Catalan scientists revealed that it is in fact from much older dates, at least 5,000 years ago. These days it has been revealed that they are even older in some cases. 
The rock art is distributed by many areas of Baja California Sur, very especially the Sierra de San Francisco, which alone hosts more than 250 sites. These sites were often occupied through millennia, until the 18th century CE in some cases. Even later they have been used as shelters for sheep, however nowadays they do enjoy state and UNESCO protection. 
The most outstanding cave, La Pintada (the painted one), appears to have indications of astronomical knowledge. In the words of Viñas Vallverdú:
In the particular case of La Pintada there are many markings of astronomical type, spots where it is indicated that the Sun illuminates in certain time of the year, signaling a date in their calendar. That way they knew that, when the Sun hit one of those marks, it was time to collect the pitahaya or that the rain period was nearing.
The research is part of an international project by IPHES and the Instituto Nacional de Antropología e Historia (INAH) of Mexico, which is surveying the prehistory of the North American federation. 
The study will be published as the doctoral thesis of lead researcher Ramón Viñas Vallverdú (IPHES).

Source: El Universal[es] (includes a very beautiful photo-gallery).

 

Epipaleolithic site dug in Sudan

Archaeologist watches a lioness head
not mentioned in the sources
A late hunter-gatherer necropolis has been discovered and researched by Czech scientists. The area of Sabalonka, some 80 Km north of Khartoum, includes a large necropolis of some 400-450 burials, believed to be from 8-10,000 years ago. Along with the burials, still awaiting radiocarbon dating, the archaeologists found a network of nearby settlements.
So far 30 skeletons have been recovered, many with personal ornaments made of shells, ostrich egg and bone. Other objects found are bone needles and domestic tools made of bone and horn.
The site is at risk in the mid-run because of a planned dam, also the researchers are somewhat concerned about funding, even though the project is low-cost. 
Sources[es]: Paleorama en Red, Radio Praga
 
 

Mouth bacteria changed with civilization… for worse

A premise of Primitivism, which is not really a doctrine or philosophy but more like realistic approach to the human condition, is that our evolutionary past is shaped almost totally by hunter-gathering. That we are basically hunter-gatherers in a jump or maybe formal suit. Why? Because some 95% of the biological history of Homo sapiens, as a formed species is one of hunter-gathering, not of productive economy nor civilization. This percentage can be extended to maybe 99.5% if we consider the whole history of the genus homo, etc. And that is a lot. 
Do I digress? Well, maybe not so much after all. The evolutionary news today is in any case that the bacterial ecosystems in our mouths have been degenerating since Neolithic, and then again with Industrialization. As Not exactly rocket science (a National Geographic blog written by Ed Yong) explains the bacteria in our mouth is not all hostile but, at least for hunter-gatherers, often balanced: some bacteria may attack our teeth but then others protect and even repair them. Much like the better known bacteria of our guts, there is a general balance in which, naturally at least, symbiosis with the human needs tends to dominate. After all those bacteria live in our mouths and therefore need it to exist in good shape: they may not be exactly “aware” of their own needs or the benefits of harm they bring to us but evolution fixes it in the long run, of course. 
Epipaleolithic foragers from Poland with a rather thick plaque, plaque that retained in millennial hibernation the bacteria of their mouth, have provided evidence of Prehistoric hunter-gatherers having a healthy, balanced mouth bacterial ecology. 
Instead Medieval English, who were already eating many carbohydrates from cereals, illustrate with their plaque the beginning of mouth bacterial decadence. There are a total of 34 studied remains between these two dates, illustrating that this change happened exactly with the Neolithic Revolution.
The members of the modern research team used their own mouths as reference for the modern bacterial environment. The results were rather depressing: industrialization has created many refined, unbalanced, foods (white cereals and sugar especially) that cause our mouths to be the boon of dentists.
We are what we eat
(source)

A similar kind of bacterial ecology decadence was observed in a previous study between the guts of Burkinabe farmers’ children and those of Italian urban ones. The latter have ecosystems dominated by well-fed firmicutes, associated to obesity.

Reference paper:  Christina J. Adler et al., Sequencing ancient calcified dental plaque shows changes in oral microbiota with dietary shifts of the Neolithic and Industrial revolutions. Nature 2013. Pay per viewLINK [doi:10.1038/ng.2536]

 

Atlantic thermohaline currents nearly stopped in some cold spells of the Ice Age

That is what researchers claim in a new study:
Stephan P. Ritz et al., Estimated strength of the Atlantic overturning circulation during the last deglaciation. Nature Geoscience 2013. Pay per viewLINK [doi:10.1038/ngeo1723]

Abstract


The Atlantic meridional overturning circulation affects the latitudinal distribution of heat, and is a key component of the climate system. Proxy reconstructions, based on sedimentary 231Pa/230Th ratios and the difference between surface- and deep-water radiocarbon ages, indicate that during the last glacial period, the overturning circulation was reduced during millennial-scale periods of cooling. However, much debate exists over the robustness of these proxies. Here we combine proxy reconstructions of sea surface and air temperatures and a global climate model to quantitatively estimate changes in the strength of the Atlantic meridional overturning circulation during the last glacial period. We find that, relative to the Last Glacial Maximum, the overturning circulation was reduced by approximately 14 Sv during the cold Heinrich event 1. During the Younger Dryas cold event, the overturning circulation was reduced by approximately 12 Sv, relative to the preceding warm interval. These changes are consistent with qualitative estimates of the overturning circulation from sedimentary 231Pa/230Th ratios. In addition, we find that the strength of the overturning circulation during the Last Glacial Maximum and the Holocene epoch are indistinguishable within the uncertainty of the reconstruction.

Summary of thermohaline circulation (public domain, NASA)
In the North Atlantic the best known thermohaline current is the Gulf Stream, which effectively keeps Europe several degrees warmer than it would be otherwise, allowing a relatively dense population at latitudes unheard of elsewhere on Earth. This current was weak at best in the Ice Age. 
Notice that they say that they can find any difference between present day (Holocene epoch) and the Last Glacial Maximum, so it cannot be inferred, it seems, that the glaciation itself had anything to do with the thermohaline currents but only with  some particular cold spells of the late Upper Pleistocene, particularly the HE1 (c. 18-14.6 Ka ago) and the Younger Dryas (c. 10 Ka ago).
 
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Posted by on February 11, 2013 in climate, Epipaleolithic, Ice Age, Magdalenian, sea

 

New rock art findings of India

A new rock art site has been found by the Archaeological Survey of India on the Satpura mountain range, near Batul, at the Maharastra-Madhya Pradesh border. The site includes nothing less that 71 rock shelters with paintings and engravings dating from c. 12,000 years ago (Late Upper Paleolithic) to recent times.


Decors comprise petroglyph’s in various forms, such as engravings,
bruising, pecking and pictographs in various colours, viz red, various
shades of red, white, black and green. The pictographs or paintings
usually illustrate human, animal, bird, tree and abstract geometric
figures and are depicted by stick figures, outlines, solid and X-ray
figures. he engravings usually exhibit elements of natural world as well
as abstract themes. The decorated shelters are spread in an area of
approximately 40 square kilometres, Sahu said. 

No pictures are available.
Source: Indian Express (via Pileta).
 

Epipaleolithic finds near Oxford, England

One of the arrowheads found
Archaeologists have found the remains of people living at Didcot (Oxfordshire, England) some 9000 years ago. Previous research had found Neolithic materials almost only but now a clear layer of hundreds of flint tools and weaponry and hearth remains has been unearthed and dated. 
 
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Posted by on January 26, 2013 in archaeology, Epipaleolithic, European prehistory, UK