Bases are found in both DNA and RNA. As seen below, they are adenine, cytosine, guanine, thymine, and uracil. They are abbreviated (A, C, G, T, U). Three of the bases (A, G, C) are found in both DNA and RNA. However, uracil (U) is found only in RNA and thymine (T) is found only in DNA.he first three are the same as those found in DNA, but in RNA thymine is replaced by uracil as the base complementary to adenine. This base is also a pyrimidine and is very similar to thymine.