702 / 2019-05-01 22:00:53

Mitochondrial Fostering: the mitochondrial genome plays a role in plant orphan gene evolution

Orphan gene,NUMT,Mitochondrial DNA,genome evolution

全体主题 > Evolution & Ecology

Mitochondrial genomes in plants exhibit odd evolutionary patterns. They have a rearrangement rate, low mutation rate, and a large size. Based on massive mitochondrial DNA transfers to the nucleus as well as the mitochondrial genome’s unique evolutionary traits, we propose a “Mitochondrial Fostering” theory where the organelle genome plays an integral role in the arrival and development of orphan genes (genes unique to a species). Two approaches are used to test this theory: 1) bioinformatic analysis of nuclear mitochondrial DNA (NUMTs: mitochondrial originating DNA that has migrated to the nucleus) at the genome level, and 2) bioinformatic analysis of a particular orphan locus present in both the mitochondrial genome and the nuclear genome of Arabidopsis thaliana. This locus codes for two orphan genes: one in the mitochondrial and another one in the nuclear genome. DNA alignments show regions of this A. thaliana orphan locus exist scattered throughout other land plant mitochondrial genomes. This is consistent with land plant mitochondrial genome’s high recombination rates. This may also enable the creation of novel coding sequences within orphan-loci, which can then be transferred to the nuclear genome and become fixed. Our study also reveals a high correlation between mitochondrial DNA rate of transfer to the nuclear genome and number of orphan genes in land plants. This suggests the mitochondrial genome has a role in nuclear orphan gene evolution.