Tightening DNA relationship

[rlgleason51]

My wife and another woman (I'll refer to as cousin for lack of better term) found each other thru family finder. My wife says they have a perfect match (don't know what that means). My wife has living sisters, but parents and grandparents are deceased. The cousin was adopted and her only known genetic relative is my wife (and wife's sisters). Given the lack of ancestors available for DNA testing, is there any DNA test available that can further define the relationship between my wife and her cousin?

Thanks

[khuebner]

Does your wife have any known cousins (both sides) who could test with Family Finder? You would want at least one paternal and one maternal. How distant does this cousin appear to be? The more distant, the more relatives you might need to test. Or you might be lucky right away. If this cousin shows as a probable first cousin, I'd think testing one person on each side would rapidly tell you a lot. If it's a more distant cousin, hard to know.

MtDNA could be useful but I wouldn't start with that as they might share a common haplogroup (so it wouldn't reveal much) or else you'd merely rule out matrilineal connection.

Having said this, I'm not an expert and someone with more experience could probably refine these suggestions.