Tekst Teda Kendella,govori o porijeklu I2-CTS10228
The main subclade of "Dinaric I2a", I-S17250, has a remarkably recent tMRCA according to YFull, of only 160 CE.
https://yfull.com/tree/I-S17250/
I-S17250 shows signs of an extremely rapid population expansion at the very start. It seems that the closest group to the ethinic origin of the I-S17250 group are the Sclaveni.
https://en.wikipedia.org/wiki/Sclaveni.
The tMRCA is right at the start of theLate Proto-Slavic linguistic period.
https://en.wikipedia.org/wiki/Proto-Slavic#Introduction
It also coincides with the Roman Emperor Marcus Aurelius' Marcommani Wars, a campaign against the Germanic Marcomanni and Quadi, and the Iranic Sarmatians, when there was a movement southward by various allied tribes into the Roman Empire.
https://en.wikipedia.org/wiki/Marcomannic_Wars
A map of the archaeological cultures of Eastern Europe in the 1st Century
https://upload.wikimedia.org/…/Rome_and_the_Barbarians_in_E…
It also coincides with the Antonine Plague which had a mortality of 25%. The Antonine Plague may have been either smallpox, acquired from trade with India, or measles, but measles in its modern form is thought to have originated a bit later. The combination of invasions from the north, including peoples who may have been associated with the Proto-Slavs, and the high mortality from the Antonine Plague, seems to have produced a strong founder effect followed by a rapid population expansion.
https://en.wikipedia.org/wiki/Antonine_Plague
I-CTS10228, the immediate ancestor of South Slavic I-S17250, according to YFull has a tMRCA of c. 200 BCE, and has members from Greece, Poland, Ukraine, Belarus, North Germany, and Finland.
https://yfull.com/tree/I-CTS10228/
This seems to correspond to some degree to peoples associated with the other two other proto-Slavic tribes, the Antes and the "Vistula Veneti" who Pliny the Elder in the 1st century calls the "Sarmatae Venedi" and Ptolemy in the 2nd century calles the "Vouenedai", a people who lived along the Baltic coast.
https://en.wikipedia.org/wiki/Antes_(people)
https://en.wikipedia.org/wiki/Vistula_Veneti
Jordanes in his Getica (c. 550 CE) says that the Veneti are the ancestors of the Sclaveni and Antes. I think then we may want to look for the origin of generally "Slavic" I-CTS10228 in the north, along the Baltic coast, rather than in regions further south and east where it is found today, where it has particularly high percentages in the Balkans.
https://yfull.com/tree/I-CTS10228/
The late Neolithic precursor of I-CTS10228, I-L621 is also found in Britain and Ireland. While I-L621 existed at the time of the Corded Ware Culture, I-CTS10228 did not expand at all until c. 200 BCE. so we can't say that it was a part of the Early Bronze Age Corded Ware expansion which took place c. 2900 BCE – c. 2350 BCE
https://yfull.com/tree/I-L621/
Interestingly, I-Y23118 is an Ashkenazi Jewish clade within the I-CTS10288 subclade I-A2512. I-Y23118 has a tMRCA of only 550 years, but along with a Pole if has a tMRCA of c. 40 CE with several Greeks from the Peloponnese as its earliest members, as well as a few Hispanics. The Hispanics can be "Saqaliba", Slavic Mamluks (slave mercenaries) who eventually took control of various small Muslim states ("taifas") after the Umayyad Caliphate collapsed in 1031. What is unusual about I-Y23118 is not that it contains Ashkenazi Jews (there were known converts to Judaism in Central and Eastern Europe in the Middle Ages) but rather that I-A2512 is both quite rare and almost completely found outside of Slavic populations.
Starting in 581 CE, large numbers of Sclaveni invaded Greece. The problem here is that the tMRCA of the Greeks is right around 60 CE, 100 years earlier than I-S17250. This is well before any movement of Germanic or proto-Slavic tribes southward into the Roman Balkans.
The earliest expansion within I-CTS10228 is I-Y4460, with a tMRCA of 200 BCE. The earliest members of this subclade are a German from Hamburg (a formerly West Slavic region), and Russians, Belarussians, Ukrainians, and a few Finns. This fits well with the Antes, who were found in Ukraine and at this early stage seem to be indistinguishable from the ancestral Veneti from further north.
https://en.wikipedia.org/wiki/Early_Slavs#Homeland
The origins of I-CTS10228 appear to be in the Baltic region among the ancestral (Vistula) Veneti ("Sarmatae Venedi"), the "Winden" or "Wends", but they appear to have made a rapid migration to the far south within 250 years of their origin, perhaps with a few captives or mercenaries living in Greece. We should also be able to trace this Baltic-originated migration southward through the mtDNA and autosomal DNA. WHG haplogroup I-M423, as represented by Loschbour, remained relatively rare outside of Sardinia until this rapid expansion, but within a few centuries, it began to dominate certain South Slavic regions like Bosnia and expand throughout the Slavic-populated areas. This shows how an essentially non-existent Y-DNA clade from one distant region can overtake and replace native Y-DNA clades as the result of a migration and expansion of a new group, and that the Y-DNA makeup of historic populations as late as the Classical Era may have been very different from the present day Y haplogroup profile in these same regions.
It cannot be coincidence that the expansion of I-S17250 took place right at the time of a major pandemic, the Antonine Plague, that killed off one quarter of the population of Europe. Clearly, it's not only migrations that change the population structure of a region, but also pandemics with high mortality. Random variations in immune system alleles can cause a new group or the children of a single random couple to dominate and partially replace a previous population lacking immunity.
