CHROMOSOME ABERRATIONS IN ANIMALS 



NONIRRADlATED IRRADIATED 



639 



X 



» 



Pm ; H Pm.Sb Cy.Sb Cy, H 



Unrelated wild -type $ 



+ ; + 

 Translocation 



No trans- 

 location 



)) 



)) 



F.tfV 



)> 



+ / + : +/ + 



Cy/+ ; H/ + 



Eggs 



Sperms 



Cy/+; H/ + 



(Crossed with unrelated 

 + /+;+/+? gives 

 Cy;H, Cy;+, +;H and 

 +;+ progeny) 



> {)()«)!> 



+ ; + 



Cy ; H Cy;+ + ; H + ; + 



)) 



)) 



)) 



)) 



Cy/+; H/+ 



Cy/+ ; +/+ 



+ /+: H/ + 



+ /+- ; +/ + 



Balanced Unbalanced Balanced 



and Duplication and Deficiency and 



Viable Inviable Viable 



Fig. 9-8. Diagram of the genetic method for detecting reciprocal translocations 

 between the second and third chromosomes in Drosophila melanogaster. Second 

 chromosomes shown at left in outline, third chromosomes at right in solid color. 

 The chromosomes with dominant marking genes carry inverted sections which are 

 not indicated in the diagram. Only crosses involving Curly and Hairless (Cy;H) 

 are detailed, but similar results are obtainable with Plum and Hairless {Pm;H), 

 Plum and Stubble {Pm;S,b) and Curly and Stubble (Cy;Sb). 



