Hi all!
I am a new member to this forum - but I am active on others. I feel that this forum would benefit from an up-to-date take on J-L70. For those interested, I do have threads dedicated to J-L70 on Anthrogenica that have evolved over time - but I'm not sure on the stance of posting links from other forums, so I will refrain from doing so.
As many of you are aware, J-L70 is a very widely spread branch of J2a. This has led to some controversy of where it originated, spread from, and so on.
So I'll start with where is J-L70 most common?
I have taken the liberty of gathering data from FamilyTreeDNA - and have reasonably large sample sizes, so these figures are likely a good reflection of J-L70's distribution in these regions. No surprise, J-L70 is most common in the Central-East Mediterranean and the Near East. These are the regions with the greatest frequencies:
Syria: 3.34% (12/359)
Italy and Malta: 3.19% (97/3040)
Lebanon: 2.12% (9/424)
Palestinian Territories: 2% (4/200)
Jordan: 1.64% (3/183)
Turkey: 1.53% (13/847) -- out of interest, quite a decent chunk are Armenians
Iraq: 1.52% (18/1184)
Greece: 1.47% (10/682)
Armenia: 1.25% (7/562)
As for which individual group has the most J-L70, it would be the Djerban Cohanim (~60%), limited to one subclade.
As we head away from these regions, we find the frequency of J-L70 drop dramatically, with most of Europe, North Africa, the Caucasus, Arabia, Central Asia etc... being <0.5%.
Within Italy, we do notice a trend of J-L70 being more common in Central Italy and Sicily/Southern Italy than the north - and there may be a reason for this, which I'll get to.
In J-L70, we find virtually all branches have a close Near Eastern relative.
The next question to address is where is J-L70 most diverse?
Here we find a pretty stark contrast between two regions and the rest of the world. The two regions with the greatest branch diversity by far are the Levant and Italy. Considering Italy's history, their diversity makes sense in context. As for the Levant, the diversity is striking given the lower levels of testing in this region, as compared to Italy and the rest of Europe
The next question to address is where did J-L70 likely originate and spread from?
The only thing we can say with utmost certainty is that J-L70 originated and spread from the Near East. Now as for specifically where, the two options that hold weight are the Levant (more so the north) and Anatolia (more so the east).
From what I have researched, a Levantine origin for J-L70 carries the most evidence, but should this not come to fruition (for whatever reason), an origin in East Anatolia would likely be the next best guess. A Levantine origin for J-L70 makes the most sense given the great branch diversity, higher frequencies than other regions, and presence of several layers of Basal branches (J-L70* in Jordan, J-FT340863 in an Sinai Egyptian and Palestinian, J-Z387* in several Sephardic Jews, and two different J-FGC35503* branches in Lebanon). Should J-L70 not originate in the Levant, this is all very coincidental. The nail on the hammer for a Levantine origin for J-L70 are the 15 distinct, distant Jewish branches. No similarly aged clade has as many distinct Jewish lineages - save for perhaps J-Y2919, but that's 600 years older. These Jewish branches are spread throughout J-L70's phylogeny, and are present in the following groups: Ashkenazi Jews, Sephardic Jews (Spain, Portugal, Italy), Sephardic Jews (Balkans, Turkey), Libyan Jews, Tunisian Jews, Djerban Cohanim, New World Conversos, Canadian Anousim, Moroccan Jews, Algerian Jews, Mountain Jews, Bukharan Jews, Italian Conversos, and Romaniote Jews. Not to mention that there are individuals from all 3 major branches of J-L70 (i.e. J-Z2177, J-CTS3601, J-PH3882) who are Cohanim. Considering Jews are a very endogamous group, and considering most conversions were on the female line, this suggests to me that the TMRCA of J-Z2148 was related to the ancestral population of all these Jewish groups in some way.
Now what about Anatolia? Anatolia doesn't display the same diversity as the Levant, nor the same level of Basal branches given similar levels of testing. The sheer number of Jewish branches contradicts an Anatolian origin. A notion of J-L70 originating in Anatolia, with some branches going to the Levant and some going to Europe isn't supported by the phylogeny we see.
What about J-Z387? J-Z387's TMRCA (7100 ybp) may be congruent with the first infusion of Late Neolithic Mesopotamians into the Levant or signals the adoption of Afroasiatic speech. An origin in Mesopotamia would make the most sense.
An origin for J-L70 amongst Romans or Greeks does not make any sense - especially given that the expansions of these civilizations occurred after J-L70's expansion period (when the greatest diversification of branches occurred). But that doesn't mean they weren't partially responsible for it's spread. Meanwhile J-L70's expansion period does correspond with the commercial prosperity of the cities of the northern Levant, with trade likely being key to J-L70's growth.
I believe J-L70 originated in Syria.
How did J-L70 spread?
There are likely many sources attributable to J-L70's spread. The primary force to Europe was likely the Syrian Auxiliaries. Much of the J-L70 we find in continental Europe and the British Isles is more than likely attributable to them. The regional trends we see do correspond with where these groups wound up. The other forces were likely less significant, being the Jewish Diaspora (for the branches surrounding existing Jewish branches), the Phoenicians (we see similar trends with other clades associated with the Phoenicians), the Greeks (via Anatolia), and the Aghlabid Dynasty (responsible for J-FGC32147 in Sicily) to name a few. Most of the J-L70 in Europe likely arrived during the Roman Period, with Rome seeing the branches spread throughout.
When it comes to Italy, I mentioned earlier that we see clear spikes in Central Italy and Southern Italy. Central Italy is likely attributed to an influx of Near Eastern ancestry during Imperial Rome. As for Sicily, J-Z387 is the highest in areas of Phoenician settlement (Mazara del Vallo and Trapani) but does display higher frequencies on the rest of the island as well. As mentioned J-FGC32147 in Sicily is more than likely attributed to the Bani Tamim (Aghlabid Dynasty).
As more how it spread throughout the Near East (which occurred before it spread to Europe), I imagine groups like the Hittites, Egyptians, Assyrians, and Amorites are all responsible for it's spread throughout.