Your mentor asks you to determine if the mutants belong to the same complementation group. What is true about flies that belong to the same complementation group? Your mentor asks you to determine if the mutants belong to the same complementation group. What is true about flies that belong to the same complementation group? They all have the same mutation in the same wing- development gene. All flies in a complementation group have identical DNA sequences for this gene. They all have some mutation in the same wing-development gene. Each strain may have a different mutation, but the same gene is mutated in all strains in a complementation group. They all have some mutation in some wing-development gene. Each strain may have a different mutation in a different gene, but all strains within a complementation group have the same phenotype.