Examples of gene structures suggestive of recombination between MSG genes. A171, G51 and A32 are three MSG sequences. A) Box diagram showing regions of identity among the three sequences. Regions that are identical for at least 16 basepairs are the same shade and pattern. B) Plots of identity (indicated by p-Distance = 0) and non-identity (indicated by p-Distances greater than zero) in pair-wise alignments of sequences G51 and A171 (upper) and G51 and A32 (lower). P-distances were calculated using a window size of 10 nucleotides and a step size of 1 nucleotide.