June 07, 2009

Lactase persistence in Greece and Italy

From the paper:
Furthermore, they indicate the existence of a genetic heterogeneity in Italy, in accordance with previous studies on classical markers (Piazza et al., 1988) and Y-chromosome (Capelli et al., 2007; see also Francalacci and Sanna, 2008). On the contrary, a substantial homogeneity was detected among Greek groups (Supporting Information Table S3), which is congruent with the only previous genetic study conducted in Greece on a multiregional scale (Di Giacomo et al., 2003).
The occurrence of lactase persistence in Greece and Southern Italy is virtually the same, which is not very surprising given the origins of the latter population.



American Journal of Human Biology
Volume 21 Issue 2, Pages 217 - 219, doi:10.1002/ajhb.20851

Tracing the distribution and evolution of lactase persistence in Southern Europe through the study of the T-13910 variant

Paolo Anagnostou et al.

Abstract

We investigated the occurrence and intra-allelic variability of the T-13910 variant located upstream of the lactase gene in 965 individuals from 20 different locations of Italy and Greece. The T-13910 frequency ranges from 0.072 (Sardinia) to 0.237 (North-East Italy), with a statistically significant difference between North-East Italians and other Italian populations. The comparison of the lactose tolerance predicted by T-13910 and that assessed by other studies using physiological tests shows a one-way statistically significant discrepancy that could be due to sampling differences. However, the possible role of other genetic factors underlying lactase persistence is worth exploring. The time of the most recent common ancestor and departures from neutrality of the T-13910 allele were assessed using three microsatellite loci. Time estimates were found to be congruent with the appearance of dairy farming in Southern Europe and the occurrence of a single introgression event. Robust signals of selection can be observed in North-East Italy only. We discuss the possible role of cultural traits and genetic history in determining these observed micro-evolutionary patterns.

Link

16 comments:

  1. I am seeing a gradient in Italy from South to North more than an hypothetical Greek origin of Southern Italians. As re A-22018 Greece has a percentage of 0,120 and Southern Italy has 0,106 but Central Italy has 0,122, I suggest to think that probably all Central Italians are of Greek ancestry.

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  2. ... or it could mean that Greeks are of Italian ancestry as well. Everything is possible.

    But the most likely is both of them share the same neolithic ancestors that were neither Greeks or Italians.

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  3. No population movements from southern Italy are known in Greece.

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  4. I would like to know where Southern Italy begins and where it ends in these studies. Does it include Sicily? Does it include Campania, but not other regions further north? For example I doubt they ever sample Molise and other place which have little in common with the South, but who knows).

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  5. Looks like a really interesting article, hope I can find it.

    I am from Tuscany and I am negative for both lactose persistence mutations (as apparently are > 75% of people from the region).

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  6. Sicily is not Italy, of course. The geographical division of Italy is simple for Italians, but the foreigners perhaps have difficulty. Italy it is the name of the peninsula only, do not confuse with the name of the Italian State the Repubblica Italiana, that includes islands. The regions of south Italy are Calabria, Basilicata (Lucania) Puglia Campania Abruzzo and Molise. Rregions Lazio Marche Tuscany and Umbria are the centre.
    However it is enough humorous that looking for the Greek roots in Italy they always are founded in the wrong places.
    Everybody thinks that they are in oriental Sicily (Syracuse), but we found them in the western part instead. In Italy all think they are in the south (Taranto, Crotone, etc.) the center seems to be more proper instead.
    Perhaps because the things are not as too many believe.

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  7. How old is this allele? Maybe it's older than "Greeks" or "Italians". Ultimately, we all came from the same place

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  8. The persistence of lactase past childhood is rare everywhere except in places with a pastoral lifestyle. The Italian rates of predicted persistence are low, even the NE Italians, compared with other Europeans further north of Italy. The fact that persistence diminishes from north or south and in the islands of Italy are not unexpected. The South of Italy and the islands would have the longest continuous settlements of farmers who use milk mainly to produce cheese, butter and yoghurts. Raw or pasteurised milk drinking by adults is uncommon. In Australia among Anglo and Irish Australians lactase persistence is over 90%, not the less than 50% estimated in NE Italians.

    The odd thing about studies of lactase persistence is that the retension of the enzyme in adults is a sign of pastoralism, the original maintence of sheep and goats, for meat, milk and other useful byproducts. This way of like is more likely in Africa and among Arabians of the Bedouin variety. Yet the persistence of the enzyme is in Europeans who are the descendants of recent movements to the north of Europe after the LGM, and a lot of those movements occurred after the Neolithic age (I.E speakers, Bronze age immigrants) whereas Europeans of the south with higher Neolithic genetic content are mostly lactose intolerant as are many modern Arabians. Both peoples one would associate with the keeping of sheep and goats. A contradiction. I suppose it shows that Southern Europeans are more settled, urbanised, agrarian, and of long residence in Europe compared to the more recent arrival of Northern Europeans from Asia with their wagons, horses and cows and nomadic pastoral existence.

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  9. Yet the persistence of the enzyme is in Europeans who are the descendants of recent movements to the north of Europe after the LGM, and a lot of those movements occurred after the Neolithic age (I.E speakers, Bronze age immigrants)

    Firstly, you forget cows, which were an early part (5,000-6,000 BCE) of the central European agricultural package, but a relatively late arriver in places like central and southern Italy. These agriculturalists were not nomads, unlike the sheep and goat herders of the south. The package that spread in central and north-western Europe also had ceramic vessels from the get-go. While initially there was no lactose tolerance to speak of in adults, and people surely used liquid fermentation and cheese making to be able to digest milk, storage and use of cow's milk for children presented no problem. How many cultures feed goat milk to their children?'

    Secondly, the number of late arrivals in central and northern Europe is very small. All evidence points to the fact that from the western half of Hungary westward (and later, northward), the people adopting agriculture ~6,500 BCE were locals. Those are the people that developed lactose intolerance later, and brought it to northern Italy with their cows many millenia later. Thus the gradient observed in Italy.

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  10. That of course should be lactose tolerance, in the above above. :0

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  11. How do you know what you have written eurologist. Bovines are native to Europe and have been since before the Paleolithic age. Those bovines were not domesticated until after the Neolithic peoples or their culture arrived in Europe. Domestication of bovines or any other animal for that matter is not indigenous to Europe but wholly Middle Eastern. Genetic studies of bovine mtDNA shows that to be mostly wholly of Middle Eastern origin except for some bovines found in far flung places like Korea and Italy. So eurologist native European dna from aurochs has entered European bovines in Italy.

    You speak of recent history, a nothingness in European terms of human settlement. The 5 to 6 kya BCE you mention is the Neolithic age in Europe. I personally do not accept the Neolithic movement of peoples into Europe with farming but many do based on various evidence. Your supposition of a local origin to Europeans who took up farming instead of people from Anatolia or the Middle East is contentious. You can't prove it nor can those people who claim from evidence of Y chromosome data of various Balkanian Europeans that agriculture is local. The facts based on archeology is that the Neolithic farmers took root in Europe including Italy and its islands 7 kya.

    The evidence shows to me, that milk drinking and the keeping of bovines for milk production is recent in Europe, and has more to do with immigrants from Southwest Asia with their horses, wagons and their I.E languages. The "Aryans" if you like, not those folks who migrated to Balkan Europe from Anotolia with their wheat, barley, beer, sheep, pigs and goats. Who knows they probably looked like Northern Indians do today more closely related to Gypsies than modern Europeans.

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  12. Two facts that may sway your thinking:

    1. There is a huge amount of evidence that shows central (and consecutively, northwestern) Europe started between 6,500 and 5,000 BCE with a full agricultural package that included ceramics and bovines. ("Organic residues preserved in archaeological pottery have provided direct evidence
    for the use of milk in the fourth millennium in Britain, and in the sixth millennium
    in eastern Europe, based on the d13C values of the major fatty acids of milk fat.... Milking was particularly important in northwestern Anatolia, pointing to regional differences linked with conditions more favourable to cattle compared to other regions, where sheep and goats were relatively common and milk use less important.")

    http://www.nature.com/nature/journal/v455/n7212/full/nature07180.html

    2. It is fully accepted in the scientific community that the advance of agriculture went along two completely different paths in Europe, along with different "packages". The southern, Mediterranean path included plants solely suitable to this region (hot and dry summers), as well as goat and sheep. The Northern path included different serials, incorporated local serials already used there several centuries earlier, and heavily relied on cattle (much better adapted to the lush, wet river plains) instead of sheep or goat (adapted to dry and mountainous chaparral).

    Once you accept the above and the documented and logically necessary local population expansion, the predominance of current European Y DNA (matching the few ancient ones found, so far, but not matching Y DNA from Anatolia or the Middle East) immediately makes sense. Populations or languages coming in from the East post agriculture? Not so much, except for the very recent (2,000 years) Slavic expansion.

    All archaeological evidence points to people with agriculture expanding north and east via Poland (relatively late because of delayed adaption of serials to the long winters and wet springs), followed by a complete re-vamping and modernization of cultures in the Ukraine and surrounding. All that "Kurgan" stuff just happened way after that, and had no population consequences in Europe that are documented until the above-mentioned Slavic expansion.

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  13. The discussion is about Greeks and Italians not Slavic speakers of whatever vintage, north, central or south. You mentioned languages, Slavic of whatever type is an I.E language, therefore very young, not as old as you claim. There is an axiom, Pots are not People. Most of that evidence you claim is scientifically proven is pure conjecture. What is lacking is real proof.

    Current DNA in Europe has nothing to do with thousands of years ago. Studies of antique DNA from skeletons of Neolithic sites, mesolithic sites and more recent age sites show little commonality with present day populations in Europe. R1b most likely entered Europe after the LGM probably in the Neolithic age. R1a was still in Central Asia in the Neolithic age. Haplogroup I was most likely in its birth place in the Middle East in the Neolithic age. Most haplogroups present in Europe before the Neolithic are most likely extinct. The British naturalist Dalton showed from a study of surnames that most surnames become extinct in about 5 generations, and that one or two surnames predominate in the population. In western Europe, R1b has predominated, in northeast/central Europe R1a, in the extremes of the southeast to northeast of Europe, haplogroup I.

    Studying haplogroups present in Europe today is like working out the shape and size of an iceberg from its visible tip.

    Indians in Asia use milk extensively, yet they do not have high lactase retension. People use milk in all sorts of ways other than drinking it: Yoghurts, cheese, butter, ghee.

    You mentioned people choosing climates to grow their plants and husband their animals. Frankly I doubt those primitives, the Neolithic age humans, had those sort of thoughts. They would have just planted their plants and husband the animals they were familiar with, sort of trial and error. Failure would have meant their moving on and trying another place. You assign too much cerebral thinking to these primitives.

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  14. Dienekes, we must also consider the fact that the Venetians were at war with the Byzantines (Greeks--religion wise--hated Catholics much more than the Turks as you know) and many Venetian soldiers mercenaries made their way to Greece.

    Where did those soldiers come from, how many stayed and what happened to them must be considered.

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  15. Greece and Italy have relationships from millennia, but I exchange him/it population exachang is always narrow and cannot have great effects on the genetic patrimony.
    Only the historical Greek colonization in Italy of the south and in Sicily has moved a consistent number of people, yet, as you can see, its biological effect is smaller than we could be thought, especially if it is compared with the cultural.
    Italy has always been a very populated country, to have some remarkable changes needs to receive a massive immigration.

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