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.

View the animation below, then complete the quiz to test your knowledge of the concept.


1	In hybridization

		A)	two DNAs from the same source combine
		B)	DNA from two separate sources combine
		C)	DNA combines with complementary RNA
		D)	DNA is split into two separate pieces

2	DNA probes are used to

		A)	locate complementary RNA sequences in a test sample
		B)	make homologous DNA
		C)	make homologous RNA
		D)	locate a specific DNA nucleotide sequence in a test sample

3	For DNA probes to hybridize

		A)	DNA strands must be homologous, having regions with similar or identical nucleotide sequences
		B)	DNA strands must be non-homologous
		C)	DNA must be complementary to RNA
		D)	DNA must be fragmented by reverse transcriptase

4	Non-homologous DNA will attach to a DNA probe.

		A)	True
		B)	False

5	At high temperature, two complementary DNA strands will anneal.

		A)	True
		B)	False

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