Final answer:
EMS is a mutagen of choice for genetic research because it induces specific types of mutations in DNA. In a strain of Drosophila lacking functional mismatch repair systems, the effects of EMS would be more severe.
Step-by-step explanation:
EMS, which stands for ethyl methanesulfonate, is a mutagen of choice for genetic research because it induces specific types of mutations in DNA. EMS chemically modifies DNA, leading to the formation of etheno adducts, which cause errors during DNA replication and repair. These errors result in mutations, making EMS an effective tool for creating genetic variation in organisms for research purposes.
In a strain of Drosophila lacking functional mismatch repair systems, the effects of EMS would be more severe. Mismatch repair enzymes play a crucial role in repairing errors during DNA replication, including those caused by EMS. Without functional mismatch repair systems, the strain would be more susceptible to the accumulation of unrepaired mutations, leading to a higher mutation rate and potentially disrupting the function of genes.