Even if they did, how would they verify that the remains are Gautama Buddha's? There are no living verified descendants. The most a DNA test could do was to show that the remains are of a person from India rather than from China or surrounding areas.
I was more thinking they could sort through the remains and figure out which ones are from the same person. Would you guess less than one percent? Interesting to think of them being purposely scattered like Catholic saints’ relics.
Should we start an “Ancient Alien” meme over this hypothetical gene testing?
The article says that the remains had been cremated.
The chances of there being any usable DNA in the bones is nil.