Figure 4

The 'less is more' hypothesis by Maynard Olson proposes that compensatory mutations can restore gene function. In the classical thinking of pseudogene evolution, once a gene has a deleterious mutation that becomes fixed, more mutations will accumulate because there is no longer any selective pressure to retain gene function. In the 'less is more' model, while the first frameshifting indel causes loss of function, it is possible for a subsequent frameshifting indel to restore gene function if it restores in-frame translation.