Miniature inverted-r4xat transposable elements (MITEs) are short DNA transposons_ To understand the distribution of MITEs in genus Oryza, the presence or absence of seven types of MITE was investigated in 44 accessions of 19 Oryza species covering nine genome constitutions. PCR and sequencing analyses showed that AA genome species harbored all of the seven types Of MITE, whereas the other genome harbored not all but zero to three types, respectively. Ditto-Osl was found to be the most widely distributed MITE: it was detected in 15 Oryza species. Phylogenic tree of genus Oryza showed that Ditto-Osl is the eldest among the seven MITEs. This study also suggests that the insertion Of MITEs is one of the major sources making genetic variations in natural populations of genus Oryza.
