Determine the amino acid sequence in a protei./predict the mRNA code for that sequence./use a complementary base sequence to attract the predicted mRNA. /find the dna fragment that binds to the mRNA. #once scientists find a gene,they can use a technique called the polymerase chain reaction to make many copies. /heat separates the dna into two strands./as the dna cools, primers are added to opposite ends of the strands. /dna polymerase adds nucleotides between the primer, producing two complementary strands. the process can be repeated as many times as needed.