The frequency of chromosome loss in Drosophila can be increased by a recessive chromosome 2 mutation called pal. The mutation causes the preferential loss of chromosomes contributed to a zygote by pal/pal fathers.The paternally contributed chromosomes are lost during the first mitotic divisions after fertilization. What phenotypic consequences do you expect in offspring of the following crosses?
Keep inmind how sex is determined in Drosophila, that loss of an entire chromosome 2 or chromosome 3 is lethal, and that the loss of one copy of the small chromosome 4 is tolerated.
X-chromosome loss at the first mitotic division in a cross between a true-breeding yellow (recessive,X-linked mutation causing yellow body colour)(female(and(a(pal/pal.father.
Chromosome 4 loss at the first mitotic division in a cross between true-breeding eyeless (recessive
mutation on chromosome 4 causing reduced eye size) female and a pal/pal father.
Chromosome 3 loss at the first mitotic division in a cross between a true-breeding ebony (recessive mutation on chromosome 3 causing black body colour) female and a pal/pal father.