Showing posts with label sheep. Show all posts
Showing posts with label sheep. Show all posts

May 18, 2014

South Asian first Neolithic and its relation with West Asia

Informative compilation of dates for West and South Asian Neolithic sites.

Kavita Kangal et al., The Near-Eastern Roots of the Neolithic in South Asia. PLoS ONE 2014. Open access → LINK [doi:10.1371/journal.pone.0095714]

Abstract

The Fertile Crescent in the Near East is one of the independent origins of the Neolithic, the source from which farming and pottery-making spread across Europe from 9,000 to 6,000 years ago at an average rate of about 1 km/yr. There is also strong evidence for causal connections between the Near-Eastern Neolithic and that further east, up to the Indus Valley. The Neolithic in South Asia has been far less explored than its European counterpart, especially in terms of absolute (¹⁴C) dating; hence, there were no previous attempts to assess quantitatively its spread in Asia. We combine the available ¹⁴C data with the archaeological evidence for early Neolithic sites in South Asia to analyze the spatio-temporal continuity of the Neolithic dispersal from the Near East through the Middle East and to the Indian subcontinent. We reveal an approximately linear dependence between the age and the geodesic distance from the Near East, suggesting a systematic (but not necessarily uniform) spread at an average speed of about 0.65 km/yr.

We must be warned that the study dwells on statistical data, mostly ¹⁴C and other archaeological dates and not in pottery typology and such. So there are probably a lot of nuances to be added to what the authors conclude. However the study is a major effort to systematize West and South Asian Neolithic dates (details in the extensive supplementary materials) and that must be acknowledged as very useful on its own.

Fig. 2 synthesizes the findings of this study:

Figure 2. A linear envelope fit to the data using the weighted dates yields the average Neolithic dispersal speed km/yr.
The filled circles (red) and triangles (magenta) show the archaeologically dated sites from Iran and the Indus valley Civilization, respectively; filled circles (black) and open triangles represent sites with multiple and single 14C dates, respectively.
[Note: Gesher is one of the earliest PPNA sites, located in Northern Palestine].

The graph is a bit misleading because there are places in South Asia with ¹⁴C dates older than the apparent 7000 BP baseline (see Appendix in the study). Ayakagytma has several dates nearing 6000 BCE (i.e. ~8000 BP), while Merhgar is dated to as early as 8520 BCE (~10,500 BP), which overlaps the oldest sites of West Asia. These oldest Neolithic sites of South Asia are hardly recognizable in the graph, as they are shown as mere dots, whose only distinction is that they are ~3000 km away from Gesher. I had to investigate the Appendix to spot them.

The Merhgar ¹⁴C date is just one but it does not seem the authors felt compelled to discard it for any reason, so it should stand in principle.

Actually, rather than explain South Asian Neolithic as West Asian derived, the data in this study only offers an interesting overview of the dates but as such demonstrates nothing. Actually, if, as they argue, we are to consider always the oldest regional date (unless unreliable), then the expansion of Neolithic to South Asia was very fast. What was rather slow was its expansion within West Asia apparently.

Said that, there are many reasons to think that there was at least an important West Asian contribution to South Asian Neolithic, if nothing else because of the important presence of several important Western Y-DNA lineages (R1a, J), which seem somehow related to Neolithic spread, as well as the so-called "ANI" component, of clear West Asian affinity. Also many crops and animals were obviously imported from West Asia.

In this regard, a reader pointed to me weeks ago to a study that claims that sheep were independently domesticated in South Asia. However I found their conclusions far fetched so I never discussed it... until now.

Sachin Singh et al., Extensive Variation and Sub-Structuring in Lineage A mtDNA in Indian Sheep: Genetic Evidence for Domestication of Sheep in India. PLoS ONE 2013. Open access → LINK [doi: 10.1371/journal.pone.0077858]

What this study did find is a very specific founder effect of sheep lineages in India. However this cannot be accepted to be caused by an independent domestication but rather looks like a founder effect after domestication, which almost certainly owes to West Asia, where the ancestors of domestic sheep lives.

Figure 3. Neighbor-joining tree of domestic sheep based on 432 bp of control region mtDNA.
(A) Neighbor-joining tree of mtDNA sequences of Indian sheep (330) along with representative samples of five lineages (▲), namely; A, B, C, D & E. Indian sheep show three lineages, namely; A, B and C. (B) Neighbor-joining tree of mtDNA sequences of the Indian (330), Chinese (129), Central Asian, Caucasian and European (406), Portuguese (161), and West Balkan (60), sheep along with representative samples of five lineages (▲), namely; A, B, C, D & E . The sequences of wild Ovis species have been used as outgroups. MEGA 5 version 5.0.1.102 was used to construct the trees using Tamura-Nei model with 10,000 bootstrap. Numbers above a given branch represent bootstrap support for the branch as a percentage out of 10,000 re samplings.

Notice please how the root of the tree is at the bottom, where the various wild species of sheep are listed by their names. So the dominance of lineage A in South Asia surely owes to a founder effect and not local domestication.

December 13, 2012

Was the first ever cheese from Poland?

Modern oscypki cheese from Poland
(CC by Pawel Swiegoda)
While today it is maybe France the most famed cheese-making and cheese-eating region on Earth*, we knew very little about cheese-making origins... until now.

Melanie Salque et al., Earliest evidence for cheese making in the sixth millennium bc in northern Europe. Nature 2012. Pay per view → LINK [doi:10.1038/nature11698]

Abstract

The introduction of dairying was a critical step in early agriculture, with milk products being rapidly adopted as a major component of the diets of prehistoric farmers and pottery-using late hunter-gatherers1, 2, 3, 4, 5. The processing of milk, particularly the production of cheese, would have been a critical development because it not only allowed the preservation of milk products in a non-perishable and transportable form, but also it made milk a more digestible commodity for early prehistoric farmers6, 7, 8, 9, 10. The finding of abundant milk residues in pottery vessels from seventh millennium sites from north-western Anatolia provided the earliest evidence of milk processing, although the exact practice could not be explicitly defined1. Notably, the discovery of potsherds pierced with small holes appear at early Neolithic sites in temperate Europe in the sixth millennium bc and have been interpreted typologically as ‘cheese-strainers’10, although a direct association with milk processing has not yet been demonstrated. Organic residues preserved in pottery vessels have provided direct evidence for early milk use in the Neolithic period in the Near East and south-eastern Europe, north Africa, Denmark and the British Isles, based on the δ13C and Δ13C values of the major fatty acids in milk1, 2, 3, 4. Here we apply the same approach to investigate the function of sieves/strainer vessels, providing direct chemical evidence for their use in milk processing. The presence of abundant milk fat in these specialized vessels, comparable in form to modern cheese strainers11, provides compelling evidence for the vessels having being used to separate fat-rich milk curds from the lactose-containing whey. This new evidence emphasizes the importance of pottery vessels in processing dairy products, particularly in the manufacture of reduced-lactose milk products among lactose-intolerant prehistoric farming communities6, 7.

See also the related article by Niddhi Subamaran at Nature News and the one by Hanna Briggs at BBC News.

The dating for the cheese-making artifacts (holed pots used to press curdled milk, discarding the whey, which is a preliminary step in cheese making) is of similar age as the arrival of Neolithic itself and the first evidences of dairying in Europe and Africa. So I guess that we can conclude that farming arrived to Europe, at least to Central and Northern Europe, together with cattle herding, dairying and cheese-making.

While the potsherds are known to exist elsewhere in Central Europe, the ones analyzed for this paper are specifically from Cuyavia, Poland, which used to be the most Northeastern offshoot of the Danubian Neolithic.

Cuajada or mamia
(GFDL+CC-BY-SA-2.5)
Just one weak caveat. While Richard Evershed (in the BBC article) asks rhetorically what other milk product could it be? This question is not as trivial as it may look on first sight because there is indeed another such milk product: the cuajada (Spanish name) or mamia (Basque name) which is nothing else but the preliminary product of cheese making (curdled milk) and a much coveted delicatessen when properly made.

But, well, I guess it can be considered a form of cheese... more or less. Also real fully-processed cheese achieves a further purpose: to preserve milk (or rather key parts of it) for delayed consumption and easier transport.

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* Actually Greeks eat quite more cheese per capita than the French, but they are the only ones. 

October 29, 2010

Do health and reproductive drive cancel each other?

This seems to be the case in a population of feral sheep from a remote Scottish island. Individuals with better immunity, and therefore longer-lived, do not manage to reproduce as successfully as their less healthy peers. However, in the long run they compensate that by participating in more reproductive seasons over their lives.

The two tendencies in dynamic equilibrium run along families.

Full story at Science Daily.

Ref. Andrea L. Graham et al. Fitness Correlates of Heritable Variation in Antibody Responsiveness in a Wild Mammal. Science, 2010. Pay per view.