Hi Glen

> Last time I left the problem of the relationship between
> IndoTyrrhenian (IndoEuropean, Tyrrhenian) and Boreal
> (UralicYukaghir, ChukchiKamchatkan, EskimoAleut), I had concluded
> that IndoTyrrhenian and Boreal had had prolonged contact, between
> approximately 8500 and 7000 BCE, after they would have diverged
> from ProtoSteppe located in the Central Asian steppes region. This
> would have caused some similarities in their early vowel systems,
> for instance (an adoption of a centralized or partially centralized
> vowel system due to areal influences stemming from NWC).

I have wondered about this too Glen. I unfortunately do not know much
about the pre-Keltiminar cultures of Central Asia to know if this
construction would work. I hoped Bomhard would settle the matter
decisively for me, but he just quotes a monograph by Nicholls which
suggests a Central Asian origin of pre PIE. As microlithic cultures
seem to have arrived in Central Asia with the Keltiminar culture only
at 5,500 BCE or so, I wonder whether this is not a little late for the
reconstruction you are suggesting.

Culturally, it appears the spread in the deserts of Transoxania acted
as an effective culture barrier to the spread of mesolithic
technologies northward from Belt Cave, Jeitun and Hissar to Central
Asiatic Keltiminar until the climatic recovery after 5,800 BCE.

But then I am a little rusty on cultures in this region. Perhaps
Alexander can help with pre-Keltiminar cultures in Central Asia.

Regards

John