In this step, also there will be the addition of complementary nucleotide from the template DNA strand. Again, for finding out the proper composition of the DNA sequence, it is important to bring this reaction to a defined stop. This again helps in the identification of the base at the end portion of a specific fragment of DNA. 16s Sequencing performs this step by removal of an oxygen atom specifically from the ribonucleotide. This particular nucleotide is known as the dideoxynucleotide.