FISH analysis is likely to detect which type of change in DNA?

Question

(a) translocations

(b) deletions

(c) frameshift point mutations

(d) a and b

Answer 1

FISH, or Fluorescence In Situ Hybridization, is based on a large fragment of DNA (the probe) with a fluorescent tag being able to differentially bind to a corresponding region on a chromosome. That is the hybridization. A translocation could be detected by the probe binding to a novel region of a chromosome where the the gene in question is not normally found. A large deletion could be detected by the absence of binding to the expected region. A frameshift point mutation would only change a single base of the DNA sequence, although the reading frame change for translation.This kind of mutation would be very difficult to detect by FISH. So a and b are possible to be detected by FISH.