Ted Kandell I looks like the Minoans from Hagios Charalambos cave on the Lasithi Plateau in Eastern Crete were in a different basal J-M319* clade from all the others today, *or* were in a very early branch of one of the ones we have today. Today, J-M319 is most common in Crete, but it's found everywhere from England and Morocco to Tibet. (Yes, Tibet!
?) However, so far, the tMRCAs of all branches of J-M319 appear to be *more recent* than the date of these Minoans from the Early Minoan III-Middle Minoan I, 2200-1950 BCE (4210-3960 ybp).
Given that every branch of J-M319 has recent *Mediterranean* representatives, could be be that all of J-M319 originated diversified in Crete with the first human settlement of the island, in the Late Mesolithic? (Even the Tibetan appears to be in "Cretan" J-M319 clade. Were these Greco-Buddhists in Afghanistan, who later fled to Tibet?)
There doesn't appear to be a rapid expansion of J-M319 anywhere outside of Crete that is typical of Early Neolithic Y-DNA clades (e.g. G-P303* and G-PF3345*, which is also common in Crete today, and certainly of Early Neolithic origin).
Interestingly, J-Y8344, which is the rare sister clade of J-M319 under J-Y5014 appears to be exclusively European. The tMRCA of J-Y5014 is the Bolling Interstadial, 14700 years ago ("the End of the Ice Age").
Also, autosomally, the Hagios Charlambos Minoans appear to be nearly identical to the earliest Pottery Neolithic people of Tepecik-Ciftlik in eastern Central Anatolia, from before 6500 BCE / 8500 ybp. (See the posts on Eurogenes about this.) Crete, like Central Greece, may have been first settled by the Early Neolithic Farmers around 6600 BCE. Even if J-M319 arrived with the Mesolithic, these Mesolithic hunter-gatherers would have been overwhelmed in numbers by the later First Farmers.
There's of course another possibility:
J-M319 arrived with the archaeologically documented migration to Crete at the 4.2 Kiloyear Event (2200 BCE). The problem with this is that this would have to involve multiple basal lineages of J-M319 which left hardly any trace in Anatolia, or anywhere to the east of the Mediterranean. At that time, the Bronze Age Western Anatolians already had some Western Hunter-Gatherer (WHG) and Steppe (EHG) ancestry, so perhaps the source was from somewhere furthern east, which had more "Caucasus Hunter-Gatherer-like" (CHG) or "Iranian Chalcolithic" ancestry.
There are some signs from J-CTS900 now that Bronze Age BR2 J-Y17946 could have arrived in Crete at the 4.2 Kiloyear Event, and perhaps other branches of J-M67 also arrived at this time and spread around the Mediterranean and into Europe with the Minoan seafarers looking for metals. If we can figure this out, we might have some real evidence about the spread of J2a around the Mediterranean in the Middle Bronze Age.
The problem with this is that there would have to be a unique specific migration of basal J-M319s to Crete around 2200-2000 BCE, who were already separated from each other by about 8000 years, without apparently leaving much trace to the east of the Mediterranean.
We can't be quiet certain yet. One thing that people here can do is at least screen the various J-M319 Cretans and all the uncategorized J-M319 subclades for the known J-M319 SNPs, and especially test or sequence those Anatolians and Cretans who appear to be in some earlier branch of J-Y20889.
The question is, is every J-M319 really of Cretan or Mediterranean Mesolithic origin, or descendants of a migration from Anatolia at the end of the Early Bronze Age?
http://open-genomes.org/genomes/Lazaridis%20(2017)/Hagios_Charalambos/Hagios_Charalambos_Minoans_on_the_YFull_5.05_tree.html