M26 is found in large numbers in Sardinia. Between 37-40% of the males there bear it. It is also found regularly in the Iberian peninsula: Basque Country, Castile, Aragon, Portugal, etc. Lastly, all of the islands in Western Europe show M26 as well: Ireland, England, the Balearic Islands, Pantellaria, etc. Some have stated that M26 must have spread, after its initial emergence, via the ocean, since it is found almost exclusively along the coasts of western Europe.
There are tens of theories on what the spread of M26 correlates to, both prehistoric and historical. Some posit it tracks the spread of Cardium Pottery or Atlantic Bronze Age culture or Megalith builders. Many now believe that M26 tracks Sardinian obsidian traders, because (a) it has been shown that Sardinian obsidian traders sailed the oceans plying their wares; (b) during that period was the only period where Sardinia was an exporter of humans; (c) and of course the large concentration of M26 in Sardinia. All of these theories relate to prehistoric happenings, of course.
Some believe M26 tracks historical migrations. Possible candidates include the Roman slave trade, the Spanish empire, or the Normans.
This exercise attempts to go through each theory as it relates to the discovery of several I-M26 in the Calabria region of South Italy. M26’s presence in Calabria could likely be the key to resolving the issue once and for all, yet this seems to have escaped modern scholarship.
Below is the list of just a few of the publicly available Calabrian clans that bear M26, tested by a major lab:
Caracciolo – exact origin unknown
Faga – Cortale, Catanzaro
Funicella – San Vincenzo La Costa, Cosenza
Gatto – Lago, Cosenza
Lamantia – Sicilian, but originally from Amantea, Cosenza
Rondinella – Gioiosa Ionica, Reggio Calabria
The presence of M26 in Calabria is rather unique, since it is the easternmost that it is found in real quantity. It also is not an obvious place for it.
Below, each theory for M26 in Calabria is stated, and how this fits in the puzzle, is examined. Then, I offer an opinion on each theory.
(1) There is no significance to Calabrian M26: Lots of Calabrians have tested M26 because DNA testing is largely an American and UK phenomenon, and Calabrians simply represent a large portion of Italian-Americans. As a threshold, this theory cannot be ignored. As anyone who participates in genetic genealogy knows, there are far more samples of R1b because home DNA testing has lots of western European participants. Under this theory, M26 would have a steady distribution across most of Italy, but would show up in so many American genetic genealogy sites simply because a large percentage of those getting tested were Italian-Americans from Calabria. Evaluation: unlikely. There is a large corpus of works testing Italians in Italy, and M26 has shown up in several regions besides Calabria. But if M26 were indeed evenly spread across Italy, we would expect to see large numbers of test kits coming back M26 from other large groups of Italian-American source populations, i.e., Neapolitans. This has not been the case. There do appear to be higher percentages of M26 in Calabria.
(2) Calabrian M26 signifies the first humans in Italy: Italy was a small refugium during the LGM and the males who existed there were M26. M26 spread along the coast of Italy and found its way to Sardinia, where it had a founder effect. Calabria, as the toe of Italy and with its inpenetrable mountains, is where the remnants of a relict M26 population were driven by subsequent invaders. M26 thus represents aboriginal Italians from way back. This theory was set out in “Mitochondrial haplogroup U5b3: a distant echo of the epipaleolithic in Italy and the legacy of the early Sardinians.” (Available for free in its entirety on Google). It is buttressed by the earliest Homo Sapiens and significant Gravettian finds being in the Calabria area. (Grotto della Romito, etc.) It also would make sense that aboriginal Italians would be slowly driven into the wild mountains at the very bottom of the peninsula, by subsequent invasions over time. Evaluation: very possible. There is an easy way to test this. Either the Calabrian M26 represents the foundational (upstream) branch, or it doesn’t. Either it shows itself to be ancestral to Sardinian M26 (and all others), or it does not. Also, Calabrian M26 samples should be very divergent from those in the rest of Western Europe.
(3) M26 was spread WEST by the cardial ware culture. Makers of Cardium pottery have been shown to have taken a western route along the Mediterranean, and cardial ware has been posited to correlate with M26. The M26 is Calabria represents those who stayed behind in Italy on the way to Sardinia. This Evaluation: possible. Again, there is an easy way to test this. Either the Calabrian M26 represents the foundational (upstream) branch, or it doesn’t. Either it shows itself to be as old as Sardinian M26, or it does not.
(4) M26 was spread EAST: M26 was spread easterly into Italy, from more western Atlantic Bronze Age cultures, or from Sardinian obsidian traders, or from Western European Megalith builders. Again, if you Google search or Wikipedia these concepts, you can readily see the various theories. Sardinian obsidian, the black gold (or more accurately, the advanced military hardware) of ages past, was spread by Sardinian obsidian traders all over western Europe, for one example. Evaluation: possible. As above, there is an easy way to test this. The Calabrian M26 should show its closest MRCA to be that of Sardinian M26, and this should be between 3000 and 4000 years ago.
Possible Historical Sources:
(5) Roman era causes: M26 in Calabria represents Sardinian slaves brought into Calabria during Roman times. Rome fought a series of wars in Sardinia around 200 B.C. They brought back vast quantities of slaves. For a while, Romans had a saying, “as cheap as a Sardinian slave.” Rome also conquered Calabria around this time, and turned vast tracts into public lands. The public lands were cultivated by slaves, and their descendants bear M26. If ~40% of Sardinian slaves bore M26, it follows that a few propagated, and entered the general population. Evaluation: possible but not likely. There were many other agricultural regions in Italy besides Calabria. If Sardinian slaves were so prevalent around Italy in 200 BC, there should be an even spread of M26 in Italy. There simply is not. Yes, there are other mechanisms (Iberian mercenaries in Hannibal’s army, Spartacus revolts) that could explain a Roman era M26 propagation. But again, these are easily testable. If Calabrian M26 represents Sardinian slaves from 200 BC (or Iberian mercenaries from the same time), those who tested positive should cluster very closely with the source populations. I don’t believe they do.
(6) Normans: M26 in Calabria represents the blood of Viking overlords. The Normans did by coincidence conquer a number of lands where there is M26: the UK, Calabria, etc. M26 in Calabria could represent the descendants of these individuals. Evaluation: unlikely. The Normans also didn’t conquer many lands where there is M26. They had no presence in Basque country, many of the Spanish states, the interior of Ireland, Pantellaria in Italy, etc. Plus the Calabrian M26 would need to cluster with Northern French M26, which it does not. Furthermore, the Norman invasion of Italy was only about 1000 years ago, not only during historical times, but at the cusp of surnames. I believe most of those testing positive for M26 from Calabria do not bear Norman surnames. (Examples of Norman surnames are Ruggiero, Gandolfini, etc.) Those testing positive for M26 from Calabria have Latin surnames.
(7) Spaniards: The Spanish ruled Calabria so the M26 there likely just comes from Spanish settlers. There is much M26 is certain provinces of Spain and therefore, if 20% of colonists, mercenaries, or adventurers bore the gene, it would make sense that a percentage of Calabrians still bear the gene today. Evaluation: unlikely. Again, easily testable: The Spanish presence in Calabria was so recent that Calabrians testing positive for M26 should be virtually identical to Spanish sources. It’s not. Moreover, some of the Calabrian families testing positive for M26 have their trees traced back to the 1500s, with only Italian names.
Taking the big picture here, you can decide. I personally think Theory (2) or (3) is most likely, that M26 in Calabria represents a very ancient people. Even in Roman times, Calabria was called the First Italy. The tribes that existed there that blended with the Romans were called the Itali (from which the entire peninsula was named). The mountains in Calabria, with dense pine forests, high peaks covered with snow, and non-navigable passes are an ideal place for the original Italian population to be found.
Comparing the STR data from these Calabrian families, it shows that they are most closely related to other Calabrians, and estimates of TMRCA among the Calabrians is as recent as 500 years ago. The next closest from what I could see from a very quick look were samples from the UK, England and Ireland, with a TMCRA back in prehistory. This would seem to eliminate theories 5-7 above.