Spontaneous mutations have been shown to occur up to 10 times more frequently in mitochondrial DNA (mtDNA) compared to nuclear DNA due to reduced proofreading activity by mitochondrial DNA polymerase. However, because there are typically multiple mitochondria per cell, a mutation in the mtDNA of a single mitochondrion may result in heteroplasmy (cells that each have mitochondria whose genomes are not all identical). In order for a mitochondrial mutation to have an effect, a certain threshold or percentage of mitochondria within a cell must carry the mutation.
Suppose a spontaneous mutation previously shown to be associated with a specific mitochondrial disease occurred within a single mitochondrion of a human gametocyte (a cell that divides to produce gametes).
Which of the following is the MOST likely possible outcome?