Both DNA and RNA are able to form hybrids in solution with other DNA or RNA molecules that have complementary base pairing. Double-stranded DNA can be "denatured" by heating to high temperature. If the resulting single-stranded DNAs are slowly cooled, the separated DNA strands can reanneal to reform the DNA duplex. Notice that A pairs with T and G pairs with C when a DNA strand hybridizes with another DNA strand. An RNA molecule can also form a base-paired DNA-RNA duplex molecule with a DNA that has complementary base pairing. The most common source of DNA complementary to an mRNA is the DNA coding strand that was the template for synthesis of the RNA. In DNA-RNA hybrid formation, G base pairs with C, A of the RNA pairs with T of the DNA, and U or the RNA pairs with A of the DNA.
