Compartmentalization and growth of the Drosophila abdomen.

An analysis of the cell lineage of the adult Drosophila abdomen is reported. Genetically marked clones are produced in the tergites in the embryo and in the sternites and pleura during larval life. The spatial disposition of the segment primordia is also studied in a series of 250 gynandromorphs. We conclude that in the embryo the segments are all separate polyclones soon after blastoderm and these are probably adjacent to each other. Gynandromorph analysis suggests that segments 2--6 develop from similarly sized cell groups but that the first tergite develops from a primordium which is equal to that of two other segments. We suggest that presumptive adult and larval cells are not separated at blastoderm. Our estimate from clonal analysis of the number of larval cells (12) which construct the sternites and pleura is equal to the number observed directly in the ventral nest of histoblasts.