A refutation to 'A new A-P compartment boundary and organizer in holometabolous insect wings.'

Abstract

We respond to a recent report by Abbasi and Marcus who present two main findings: first they argue that there is an organiser and a compartment boundary within the posterior compartment of the butterfly wing. Second, they present evidence for a previously undiscovered lineage boundary near wing vein 5 in Drosophila, a boundary that delineates a "far posterior" compartment. Clones of cells were marked with the yellow mutation and they reported that these clones always fail to cross a line close to vein 5 on the Drosophila wing. In our hands yellow proved an unusable marker for clones in the wing blade and therefore we reexamined the matter. We marked clones of cells with multiple wing hairs or forked and found a substantial proportion of these clones cross the proposed lineage boundary near vein 5, in conflict with their findings and conclusion. As internal controls we showed that these same clones respect the other two well established compartment boundaries: the anteroposterior compartment boundary is always respected. The dorsoventral boundary is mostly respected, and is crossed only by clones that are induced early in development, consistent with many reports. We question the validity of Abbasi and Marcus' conclusions regarding the butterfly wing but present no new data.

Molecular mechanism underlying venation patterning in butterflies

“…A recent report proposed the presence of a second dpp -like organizer at the far posterior compartment in butterflies ( 26 ). This report, however, showed no direct gene expression or functional evidence and has been debated by other researchers ( 27 ). Currently there is also no functional evidence of altered venation for knock-out phenotypes for any of these genes in Lepidoptera.…”