Figure 11. Models.

(A) Model for the elimination of segmentally aneuploid cells from imaginal discs. Cells that lose part of one chromosome may become haploinsufficient for one or more Rp loci, affecting ribosome assembly and triggering RpS12 and Xrp1 activities that lead to cell elimination by competition with unaffected neighboring cells. (B) Our studies show that segmentally aneuploid cells proliferate and contribute to adult tissues in animals where all cells are heterozygous for an Rp mutation, reducing the difference between aneuploid and diploid cells. A similar situation might apply in Diamond-Blackfan patients, many of whom are haploinsufficient for Rp loci. If Rp loci are also indicators of chromosome rearrangements in mammalian cells, such patients might face a greater accumulation of aneuploid cells.