In constructing an oligonucleotide probe based on information from a protein's sequence, one often chooses, if possible, regions of a sequence containing tryptophan or methionine residues. Why?

As the two amino acids have only one codon, the oligonucleotide probe will have a greater specificity for the DNA which Correct precisely the sequence of the probe that matches that of the target sequence, the fewer false positives one will encounter.