Nucleotide sequence of Suncus murinus immunoglobulin mu gene and comparison with mouse and human mu genes.

Both primates and rodents apparently originated from insectivores and then evolved separately. We isolated the immunoglobulin mu gene from DNA of the insectivore Suncus murinus and determined its nucleotide sequence. The gene organization was CH1 exon (318 bp)-intron (89 bp)-CH2 exon (345 bp)-intron (80 bp)-CH3 exon (318 bp)-intron (85 bp)-CH4 exon (392 bp)-coding sequence and 3'-untranslated region. Comparison of nucleotide sequences of mu genes between mouse, human and Suncus murinus indicated that the evolutionary distance between human and mouse is equal to that between Suncus murinus and human, and that mouse is deviated further from Suncus murinus than the two other combinations. This conclusion was further supported by sequence comparison of non-coding regions.