Fig. 3. Morphological alterations in DA neurons caused by Fmr1 mutations. (A,B) Ventral DA neurons in the A5 segment of a wild-type larva (w¹¹¹⁸) (A) and a Fmr1⁴ mutant larva (B) were labeled by UAS-mCD8::GFP. The images were taken from live animals, and all the dendritic processes could be visualized. (C) All ends in a specific area between the two ventral clusters of DA neurons in the A5 segment were counted to determine the number of dendritic processes per 1000 µm² (n=38 for wild-type, n=35 for mutants, ***P<0.001). All the values are mean±s.e.m. To rescue the dendritic phenotype in Fmr1 mutants, a chromosome containing a 14 kb fragment that spans the Fmr1 transcriptional unit (Dockendorff et al., 2002) was introduced into the Fmr1⁴ mutant background. (D) The distribution of individual larvae with different numbers of dendritic ends illustrates the differences among individual animals of the same genotype and between wild-type and mutant larvae. Scale bars: 40 µm.