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Fig. 4. Olfactory precursors and amos/ato expression. (A,B) ato
is expressed in the wave 1 precursors. The arrows mark the ends of this
semicircular line of olfactory precursors. ato-dependent arista
precursors (*) and chordotonal precursors (caret) are also marked. (C,D)
ato is expressed in the wave 2 olfactory precursors (bracket). It is
not expressed in the third wave, the first cells of which can be seen between
the Ato rows (arrows in D). (E,F) amos is expressed in a
complementary way to ato in the third wave of precursors. (E)
Confocal projection of a stack of images showing Amos detection in a similar
disc to D. (F) Deep confocal section from E showing nuclei of
amos-expressing precursors (arrows) underlying the main amos
proneural expression domain. These correspond to the non-Ato-expressing
precursors (arrows in D). (G) Schematic summary of amos- and
ato-dependent precursor pattern at
8 hours APF.