"Research fit" or "Inbreeding coefficient"?

[Forest]

Do you guys have any idea how to differentiate "research fit" and "inbreeding coefficient"? If I have some collaborative research experience with the professor who I am interested in, does this case mean "research fit" or "inbreeding coefficient"? I am not an undergraduate student in the university which I apply, but spent a summer in one lab there. I am afraid the admission committee would consider my case as the latter one.

[Pnictides]

This is an interesting question. I want to know this too.

[Eigen]

I don't think it would be considered too much- in fact, we encourage undergraduates interested in applying to our program to try to come do some summer undergraduate research so they can get a feel for the place (and the faculty for them).

Inbreeding is something that people worry about more when you're applying for faculty jobs than when you're applying for grad school, imo. It's not uncommon for people to do a BS/PhD at the same school- the school won't really think it's a big deal, it's just not the best for the student later on to not have multiple different programs behind them.