Fig. 2. Differential screening of a subtracted lemma/palea cDNA library from elongating stage. Duplicate filter arrays of random clones (probes) from the elongating stage lemma/palea library were hybridized with 32P-labeled cDNA populations of 106 cpm/mL activity made from (A) forward subtracted cDNA (lemma/palea, tester; flag leaf, driver) and (B) reverse subtracted cDNA (flag leaf, tester; lemma/palea, driver). Clones in panel A showed differential hybridization and therefore represent mRNA sequences for genes highly expressed in the lemma/palea. The position of clones on the filter arrays is depicted in the table below.