A gene product thought to be involved in the down-regulation of fetal hemoglobin expression is being investigated. Samples of primary tissue cultures of fetal, neonatal, and adult liver and bone marrow, as well as adequate amounts of a DNA probe believed to contain the studied gene, are provided. Which of the following techniques is the best for determining the tissue culture sample that is expressing the gene of interest?

1. A)Southern blot
2. B)Polymerase chain reaction (PCR)
3. C)Northern blotGABARITO
4. D)Western blot
5. E)DNA sequencing