Figure 4.—
The nucleotide sequence of repeats of the variable region. Repeats of the variable region can be divided into four types: K, N, α and δ. Repeats K and N are also found in the constant region, whereas α and δ are virtually specific to the variable region. All α-repeats possess a CAA codon at position 6, while δ-repeats possess CCT at the same position. Variant α- and δ-repeats are indicated by a superscript and only their specific nucleotides are written. Nucleotides differing from the murid consensus are in boldface type. We had previously designated the repeats that compose the variable region of the expanding alleles of Swiss mice as K′, L2, M2, N, β and γ (Delhomme and Djian 2000). In view of the nomenclature adopted for the repeats of wild-derived mice, and of the clear similarity of these repeats with those of Swiss mice, we changed the designation of the repeats of the variable region of Swiss mice: K′, L2, and β became K3, α14, and α23, respectively, while M2 and γ both became α1.