Jewish Genealogy by DNA.

I am a amature genealogist and have done the DNA test through Ancestry.com. All it was able to tell me was that my ancestors came from the Middle East (defenitelt worth the $100 something dollars!).

I would like to do a more specific test for ashkenazi Jews. I once read that scientist say that the DNA of Ashkenazi Jews shows that all Ashkenazi Jews come from the same four woman about 1,000 years ago.