I would like to add my Humble comments from a Layman's point of view.
I was a front line para medic in the IDF and have attended some Halacha
And Medicine conferences as was as using my wife's knowledge as a member
of the staff of the Sackler School of Medicine of Tel Aviv University.
In extreme cases of mutilation of the body, teeth are used as well as
identifying metal "dog tags" on soldiers. DNA finger print or blood
samples have been used to piece body parts together on bus explosions.
Recently there was a discussion on Kol Yisrael (Natl. Radio) about the
fact that it can be proven that Kohanim have a single paternal ancestor.
As for maumzerut, most Rabbis do their best to find a way out for the poor
individual. Why look for a Chumra.
DNA mapping like fingerprints and the shape of the ears, nose, scars, etc.
can help (in my opinion) release an Aguna. But I am not an expert in all
the minute details of Halacha and there is an Institute of Technology and
Halacha in Yerushalayim that deals with these problems.
Richard (Rachamim) Pauli