Mitochondrial fostering: the mitochondrial genome may play a role in plant orphan gene evolution (bioRxiv)
Orphan genes are those that are found in only a single species. In trying to understand the origin of orphan genes, O’Conner and Li have found that many of these orphan genes are likely to have originated as mitochondrial genes, as many are nuclear genes whose encoded proteins are targeted to the mitochondria through encoded targeting peptides. Although mitochondria are derived from bacteria, they retain few genes, with most of their genes having migrated to the nucleus (as much as 98% of mitochondrial genomes can be non-genic). Interestingly, most of the 30 Arabidopsis orphan genes encoded in the mitochondrial genome are also present in the nucleus, further supporting the model that many orphan genes are mitochondrial in origin. Interestingly, mitochondrial genomes have high rates of rearrangement, which could generate the novelty that creates orphan genes. Due to the role of mitochondria in cultivating orphan genes, the authors describe this effect as mitochondrial fostering. (Summary by Mary Williams) bioRxiv
