A possible model for integration of the sequence (unique region IV) in Ogura-type mitochondrial genome. Yellow small arrows indicate identical 176-bp inverted repeats at the edges of regions 7 and 11. On the insides of these repeated sequences, another pair of 28-bp inverted repeats is present (purple small arrows). Unique region IV had been integrated into radish mitochondria genome via these repeats when recombination between syntenic regions 7 and 11 occurred.
Tanaka et al. BMC Genomics 2012 13:352 doi:10.1186/1471-2164-13-352