develops from
directly develops from
TODO - add child relations from DOS
has developmental precursor
Chris Mungall
FBbt
David Osumi-Sutherland
Candidate definition: x directly_develops from y if and only if there exists some developmental process (GO:0032502) p such that x and y both participate in p, and x is the output of p and y is the input of p, and a substantial portion of the matter of x comes from y, and the start of x is coincident with or after the end of y.