Can bitcoin be merge mined with bitcoin?

[wingding]

From bitcoin wiki I understand that any SHA256 coin can be merged mined with bitcoin, hence my question.

And my follow-up question is; can a bitcoin clone with a separate blockchain be merged mined with bitcoin?

[domob]

Only coins that explicitly support being merge-mined can be - so the answer to (both) your questions is no.  Furthermore, Namecoin, for instance, is a coin that explicitly allows both non-merge-mined and merge-mined blocks - but it has explicit provisions to prevent anyone to merge-mine it with itself (for good reason, obviously).