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figure 3

Figure 3 - Examples of human immunoglobulin V, D and J gene recombination signals

Although the heptamer and the nonamer sequences are well conserved, there are sequence differences between individual genes. Spacer lengths are 12±1 or 23±1 bp. This is known as the 12/23 rule [Early P. et al. Cell 19, 981-992 (1980), PMID: 6769593]