If You Knew the Sequence of a Gene in One

If you knew the sequence of a gene in one organism, how could you determine if another organism had a similar gene?

A) treat the genomes of both organisms with the same restriction enzyme and compare the patterns of the bands produced with gel electrophoresis
B) insert the known gene into a vector and use the vector to insert the known gene into the other organism
C) create labeled DNA probes from the known gene and use them to screen the DNA library of the other organism
D) create a hybrid of the two organisms by breeding them and check for mutations