  We model and discuss advantages of pan-editing, the complex way of expressing
mitochondrial genes in kinetoplastids. The rapid spread and preservation of
pan-editing seems to be due to its concomitant fragment dispersal. Such
dispersal prevents losing temporarily non expressed mitochondrial genes upon
intense intraspecific competition, by linking non expressed fragments to parts
which are still needed. We mathematically modelled protection against gene
loss, due to the absence of selection, by this kind of fragment association.
This gives ranges of values for parameters like scrambling extent, population
size, and number of generations still retaining full genomes despite limited
selection. Values obtained seem consistent with those observed. We find a
quasi-linear correlation between dispersal and number of generations after
which populations lose genes, showing that pan-editing can be selected to
effectively limit gene loss under relaxed selective pressure.
