Assertion: adenine base | /r/CapableOf | substitute for another pyrimidine base
Facets:
Source sentences:
text: Transition mutations occur when a pyrimidine base (i.e., thymine [T] or cytosine [C]) substitutes for another pyrimidine base or when a purine base (i.e., adenine [A] or guanine [G]) substitutes for another purine base.