DNA Probe (DNA hybridization)
How do you find a particular DNA sequence in a sample?
The isolation of specific DNA sequences from a tissue sample was a challenge for early molecular biologists.
Unlike proteins, which have diverse sizes and charges, there is no easy way separate out a specific sequence of DNA based on its general physical and chemical properties.
You cannot chemically stain for a specific sequence of DNA.
In contrast, it is often possible to use a specific stain to detect a specific protein.
Once a DNA sequence is known, the complementary strand can be synthesized and used to detect the strand of interest in a sample.