Source for gDNA across phyla?

[Michael Myers]

Is there a company that sells genomic DNA from organisms representing
phylogenetic branchpoints? I am considering a stepwise approach to cloning
a homolog from a higher organism, and it's already clear from Southerns
that if one exists it has diverged a fair degree.

Any summary references regarding approaches to isolating homologs would
also be appreciated. I have often wondered if someone hasn't put together
a synopsis of the various methods (low stringency hybridization,
degenerate PCR). A literature search didn't give me anything.

Thanks,

-- 
Michael Myers
The Laboratory of Genetics
The Rockefeller University
212-327-8233
myersm at rockvax.rockefeller.edu