Effects of caffeine on chromosomal loss and nondisjunction in Drosophila melanogaster

Three types of male larvae, normal X males and two types with structurally abnormal X chromosomes (ring X and short X sc⁴sc³, y) were treated during the third instar with 0.5 per cent caffeine in nutrient medium. Upon eclosion, these males were mated to yellow and Oregon-R wild type females. The F₁ generation of each cross was scored for normal (XX and XY) and abnormal (XO and XXY) progeny. Statistical analyses of data demonstrate that caffeine increases chromosomal loss for all genotypes tested. The effect of caffeine on nondisjunction, however, is not clear. There are at least marginal increases in all cases when Oregon-R females are used. Slight increase and decreases noted for offspring of yellow females appear to be dependent upon the genotype of the inseminating male.