Students use this laboratory exercise, restriction enzymes to recognize a four-, six-, and eight-nucleotide sequence. Assuming that the four component nucleotides (A, C, T, G) are distributed randomly within a DNA molecule, then any four nucleotides can occur, on average, every 256 nucleotides, a six-nucleotide recognition site occurs every 4096 nucleotides, and an eight-nucleotide recognition site occurs every 65,536 nucleotides.