Y-DNA of the Pre-Hellenic inhabitants of Greece and Crete, the Early Helladic and Minoan people.

The Early Helladic stands in stark contrast to the Later Mycenaean, not just due to the presence of Steppe Lineages, but also a stark decline of the previous dominant lineage, J1b-F1615, which is extremely marginal in the Mycenaean period.
L, I2a and J1a vanish completely after 1700bc, and new Lineages such as J2b-L283, R1b-Pf7562, R1b-M269, C1a-V20, , J2a-PF7416, J2a-PF5197, J2a-PF5007, and G2a-P287 appear, which are Absent in the preceeding periods.

Crete sees more continuity from the Minoan to the Mycenean periods, however J1 disappears as well, G2a grows dramatically, and R1b-PF7562 and E-L618 (E being absent on the mainland) appear.

This speaks for more than just an introduction of Steppe Lineages at the switch from Helladic to Mycenaean Civilization, but also attests other migratory events seperate from the Proto-Greek movement happening paralell to it into Greece.