MEGA MITOCHONDRIA: Researchers find that two flowering plants in the Silene genus (above) have comparatively enormous genomes in their mitochondria, an organelle with a high mutation rate. YALE UNIVERSITY
D.B. Sloan et al., “Rapid evolution of enormous, multichromosomal genomes in flowering plant mitochondria with exceptionally high mutation rates,” PLoS Biology, 10 (1) e:1001241, 2012.
Based on high mutation rates seen in small mitochondrial genomes, researchers hypothesized that elevated mutation rates would result in smaller streamlined genomes with less noncoding DNA. But Daniel Sloan at the University of Virginia found that mutation rates aren’t always linked to size. Sloan identified two enormous, rapidly mutating plant mitochondrial genomes, suggesting that other mechanisms may regulate genome size.
Mutations within coding regions are risky, but adding more noncoding DNA compounds the risk. Mutations in noncoding sequences can create false start-sequences and other nonsense code that can impede the normal function of the cell as much as mutations in ...
