Fig. 9-5. Salivary-gland chromosomes of Drosophila melanogaster. Rearrangements 

 detected in larval progeny of irradiated fathers, (a) Unaltered complement; chromo- 

 somes aggregated at their proximal heterochromatic regions to form the chromocenter. 

 (Insert shows chromosomes of neuroblast cell, not from same individual but photo- 

 graphed to same scale as salivary-gland chromosomes.) (6) Transposition of section 

 of right limb of third chromosome, (c) Inversion in X chromosome; inversion loop 

 surrounds nucleolus, (d) Intercalary duplication (reverse repeat) in left limb of 

 third chromosome. (Photographs of preparations by the author.) 



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