B-cells and T-cells are major components of immunity that detect a large variety of antigens that enter the body. Immunoglobulin (B-cells) and T-cell receptor diversity is developed through somatic recombination. The method utilized by the cells is called V (D) J recombination. The three gene segments that are involved in this somatic recombination include V (variable), D (diversity), and J (joining). V (D) J recombination utilizes several components in the formation of the variable regions. RAG-1 and RAG-2 initiate the process of this recombination by nicking the double-stranded DNA between each gene segment and its bordering recombination signal sequence (RSS), which consists of a conserved region that borders the site of DNA cleavage. RSS sequences flank the coding receptor DNA that is sought out for recombination. The RSS contains a conserved heptamer (CACAGTG) and nonamer (ACAAAACC) separated by 12 to 23 DNA base pairs. RAG-1 recognizes the heptamer and nonamer binding sites. Even though there is knowledge that a variety of nucleotides are involved in sequences that are most commonly found to be involved in V (D) J recombination are shown to have conservation of nucleotides at certain frequencies. Currently there is hope to determine recombination frequency of nucleotides. This information is important to know where RAG-1 most likely binds to as well as what V (D) J gene segments determine the diversity of B-cell and T-cell receptors.