Any conserved heptamer (7-nucleotide)-nonamer (9-nucleotide) sequence, separated by a 12 or 23 base spacer, which occurs 3′ of variable gene segments, 5′ and 3′ of diversity gene segments, and 5′ of joining gene segments, in both immunoglobulin (Ig) and T-cell receptor (TCR) genes. It functions as a recognition sequence for the recombinase enzymes that mediate the gene rearrangement process involved in the generation of lymphocyte antigen receptor diversity.