Cw. Birky, UNIPARENTAL INHERITANCE OF MITOCHONDRIAL AND CHLOROPLAST GENES - MECHANISMS AND EVOLUTION, Proceedings of the National Academy of Sciences of the United Statesof America, 92(25), 1995, pp. 11331-11338
In nearly all eukaryotes, at least some individuals inherit mitochondr
ial and chloroplast genes from only one parent. There is no single mec
hanism of uniparental inheritance: organelle gene inheritance is block
ed by a variety of mechanisms and at different stages of reproduction
in different species. Frequent changes in the pattern of organelle gen
e inheritance during evolution suggest that it is subject to varying s
elective pressures. Organelle genes often fail to recombine even when
inherited biparentally; consequently, their inheritance is asexual. Se
xual reproduction is apparently less important for genes in organelles
than for nuclear genes, probably because there are fewer of them. As
a result organelle sex can be lost because of selection for special re
productive features such as oogamy or because uniparental inheritance
reduces the spread of cytoplasmic parasites and selfish organelle DNA.