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How far back can DNA trace past ethnic strands

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  • How far back can DNA trace past ethnic strands

    I am Italian by birth and upbringing and my ancestors were to my knowledge all Italian at least until as early as the early XIX century, which is as far as I can go .
    Both my paternal and maternal great grandfathers were in fact born at about that time.
    Italy has been a melting pot of many, many cultures and peoples throughout its long history: the Greek colonization of Southern Italy and Sicily in the VIIth century B.C. until the Roman conquest, when they were assimilated into the Roman fabric, then the Roman Empire, itself a melting pot of diverse Germanic, Celtic, Middle-Eastern and North African people and, to top it all, the Germanic invasions of Northern Italy in the early Middle-Ages , notably the Lombards from Scandinavia ,who ruled Italy for almost three centuries, in addition, of course, to the Arabs and the Normans of Sicily in the Xth and XIth cent., lasting for another two centuries.
    Furthermore, we still have today in Southern Italy and Sicily, pockets of Greek and Albanian populations in a few scattered towns and villages, descending from Christians fleeing the Ottoman conquest of Anatolia, Greece and the Balkans in the 14th century. They still speak their ancestral languages and are of Greek-Orthodox religion.
    I am sure that this diversity must somehow be present in my DNA, even more so that on the paternal side I have Sicilian ancestry ( my grand-father) while on the maternal side we are all Northern Italian from Lombardy ( Milano and Pavia), the latter the seat of the Lombard Kingdom for three centuries.
    In fact the ethnic imprint of both the Germanic and the Mediterranean people ( Greeks, Arabs and North African Berbers ( as most of the “Arab” Moslem invaders were) is still visible today among Italians , albeit in a variety of shades : in some cases you can’t tell a Sicilian from a North-African just as you can’t tell many Lombards and Northern Italians from a German or a Suede ( blondism reaches a staggering 20% in North-East Italy near the Alps, the gateway of the Lombard invasions, a region where the average height of the Italian population is, significantly, above the Italian average.

    Here are my questions. Please address them one by one specifically.
    If my ancestors have been at one point or another, even as early as the Middle Ages or possibly before, of North African, Germanic, Greek or Arab/Middle-Eastern stock, can DNA analysis reveal these different ethnic strands so far back in time?
    Q2 How far and how precisely can DNA reach back in determining one’s ethnic mix ?
    Q3.Can it be done through genotyping or by other more complex ( and probably more expensive) procedures, like whole genome sequencing?



  • #2
    Originally posted by ittiandro View Post
    If my ancestors have been at one point or another, even as early as the Middle Ages or possibly before, of North African, Germanic, Greek or Arab/Middle-Eastern stock, can DNA analysis reveal these different ethnic strands so far back in time?
    Certainly, depending on the calculator. Eurogenes K36 is a deep-ancestry test and has an advantage for Italians in that it reads Middle Eastern DNA elements correctly from within the past 2,000-3,000 years but not so far back that it conflates it with the Anatolian ancestors who moved into Europe before 9,000 years ago. That is why Italians and Jews score some portions of the elements "Arabian", "Armenian", "East Med", and "Near Eastern" in that test while most Northern Europeans score little or none in those categories.

    Various calculators at GEDmatch can be used to paint each chromosome you have to see where you have elements that have Mediterranean, North-Central European, Balkan, Middle Eastern, or North African affinities.

    Jewish DNA from ancestors within the past 600 years exists in some Sicilians and presumably Calabrians too and can be determined by finding Jewish matches to particular autosomal DNA segments or by closely matching Jews in the Y-DNA screen.

    But the most accurate identical-by-descent analysis on very short segments (below 5 or 6 cM) to find early-medieval or ancient connections between populations can only be done by scientific labs, at this time.


    • #3
      One problem is that every child gets a RANDOM 50% OF each parent's DNA. getting a random half at each generation means that if you go back a few generations, you have ancestors from whom you received no DNA.

      Another problem is that people in Europe have been mixing so freely for so many thousands of years that it's virtually impossible to find a "pure" population to use as measuring stick. Each company uses population samples from places that they think were relatively isolated and therefore representative of a given ethnic group, but no one is certain.

      Ethnicity testing is most accurate when it comes to the continental level. It's not much of a problem determining if you are Chinese are European, but when it comes to separating ethnicities in Western Europe, it's almost impossible.

      My paternal grandmother was from Sicily and my paternal grandfather was from Cappelle sul Tavo in Abruzzo. In the 1700s people were brought over from Yugoslavia because there was a shortage of workers. I can't see any evidence of Yugoslavian ancestry in my fathers ethnicity results, but I can see from the names of his matches that one or more of these immigrants must have been his ancestor(s).