A geneticist wants to isolate mutants in mice that are defective in nucleotide-excision repair (NER) but is unable to do biochemical analysis on the NER system so must use some other method to identify putative NER mutations. Which of the following would most likely be useful in identifying NER mutations in mice?1. Identifying possible NER mutants by their progeny consisting of a reduced number of females with a normal number of males when they are crossed to normal mice
2. Identifying possible NER mutants by their high spontaneous mutation rates for base-pair substitution and frameshift mutations
3. Identifying possible NER mutants by their increased susceptibility to UV irradiation compared to normal mice
4. Identifying possible NER mutants by their high rate of cytosine deaminations compared to normal mice
5. All of the above would be characteristic of NER nutants