In Drosophila, mutation screening usually involves use of a balancer chromosome that includes three elements: a set of overlapping inversions, an easily recognized dominant mutation, and a recessive lethal mutation that prevents balancer homozygotes from surviving. Which one, or combination, of these elements is necessary and sufficient to suppress crossovers?
A) lethal recessive
B) inversions plus dominant
C) inversions
D) lethal plus inversions
E) dominants

Question

Quizplus · Accepted Answer

Inversions are necessary and sufficient to suppress crossovers in Drosophila because they rearrange the genetic material in such a way that crossover events between the inverted segments and their homologous sequences in a non-inverted chromosome can lead to non-viable gametes, effectively preventing recombination within these regions.

In Drosophila, Mutation Screening Usually Involves Use of a Balancer