It's my opinion since a long time (but it can change, of course) that megaliths were made by later generations of Neolitic farmers; some scientists think that even the philosophy of megalithic people was different from the dominant one among first farmers from SE and Anatolia. Their mortuary habits were surely different, with links tied almost tightlier to territory/place than to few generations family. Someones in the same track think this could be the reflect of Mesolithic HG's conception rather than of southeastern farmers ones. Only guesses.
It's striking how strong is the reapparition of Y-I2a2 (first place) and Y-I2a1b among megalithic people. What occurred in some places of Carpathian Bassin (aside the megalithic question) occurred also in Atlantic Europe. I don't believe in a hazardous coincidence. It would be interesting to study deeply the mt-DNA too. What seems sure is that this phenomenon IN EUROPE seems rather occidental since 4000 BC spite born in central Mediterranea between 5000/ 4000 BC) and ATW maritime at first before expansion. It seems that in Scandinavia it was culturally but ALSO DEMICALLY (Coon) linked to the Long Barrows phenomenon which interacted with TRBK. It's good play to say that the successions of diverse forms of megaliths does not indicate a filiation between them, but in Germany by example it seems megalithism came from North Sea and maybe Atlantic; in France, the very dense dolmens of South followed in time the Brittany ones (if new studies don't say otherwise). For North of East Germany, Wiki says:
" The megaliths in Mecklenburg-Vorpommern were erected as burial sites in the Neolithic, by the bearers of the Funnelbeaker (TRB) culture,[1][2] between 3,500 and 3,200 BC.[3] Initially, the TRB people buried their dead in pits, often covered with mounds of clay.[2] Later, they erected dolmens for this purpose,[2] but also continued the use of flat graves.[1] All megaliths were erected during a relatively short time period, spanning about 200 years or about seven generations, with the oldest ones dating to phase C of the Early Neolithic, while most were built in the beginning of the Middle Neolithic."
Physically, the most of the Megalithers pops, despite not completely homogenous, presented often kind of more robust type of so called 'mediters', with
some accretions of Mesolithic diverse types or say populations, often on a "cromagnonlike"* direction in a rough sense,
not contradicted by auDNA, specially along Atlantic coasts and Iberia (around 25 to 30% of WHG).
*: not to say they were direct descendants of old-old "grand'pa Croma" of course, this to prevent any attack;
concerning West Caucasus Wiki says:
"Concentrations of megaliths, dolmens (Adyghe: исп-унэ) and stone labyrinths dating between the end of the 4th millennium and the beginning of the 2nd millennium B.C. have been found (but little studied) throughout the Caucasus Mountains, including Abkhazia. Most of them are represented by rectangular structures made of stone slabs or cut in rocks with holes in their facade. These dolmens cover the Western Caucasus on both sides of the mountain ridge, in an area of approximately 12,000 square kilometres of Russia and Abkhazia. The Caucasian dolmens represent a unique type of prehistoric architecture, built with precisely dressed large stone blocks.[citation needed] The stones were, for example, shaped into 90-degree angles, to be used as corners or were curved to make a circle....".
these dolmes are different enough from the occidental ones, but what is amazing is that there again the apparition of megaliths is rather
late compared to first apparition of agriculture in close S-E Europe.
Curiously, the strong implantation zone of dolmens i western France and central-southern France doesn't include Gascogne nor Basque region.
My remarks here are a bit "gross" en generalizing too much; a precise study of distributions of mt- and Y-haplos with big enough samples well levelled by region could prove or disprove demic connections and cultural ones.
