Most important, they can't read the 3 billion letters--A, C, T and G, for the nucleotides adenine, cytosine, thymine and guanine--in the human genome from beginning to end, the way one reads a book.
The terms sense and antisense were coined by Paul Zamecnik to show the complementary, double-strand nature of DNA. One strand consisted of alternating patterns of the four nucleotides that make up DNA adenine, cytosine, guanine and thymine and it could be read in order.