Sequence evolution in B-type repeat units. Multiple alignment of the consensus sequences of B-type repeat units of (A) SVA2, SVANLE, PVA, FVA, SVA and (B) LAVA elements. B’ denotes the second B-type repeat in the 5’ repeat unit arrays of SVA_B to SVA_F. B5’ refers to the 5’-most B-type repeat unit in orangutan SVAs (in A) and LAVA_B2 (in B). B_CCA is the subfamily specific internal B-type repeat unit of LAVA_B2C. MMU – Macaca mulatta; NLE – Nomascus leucogenys; SVA_PA – orangutan (Pongo abelii) SVAs; SVA_PtA – chimpanzee specific SVA subfamily. The corresponding alignments for all other repeat unit types are provided in Additional file 1: Figure S1.