- Our Impact
|Title||Selfish Little Circles: Transmission Bias and Evolution of Large Deletion-Bearing Mitochondrial DNA in Caenorhabditis briggsae Nematodes|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Authors||Clark, KA, Howe, DK, Gafner, K, Kusuma, D, Ping, S, Estes, S, Denver, DR|
|Type of Article||Journal Article|
Selfish DNA poses a significant challenge to genome stability and organismal fitness in diverse eukaryotic lineages. Although selfish mitochondrial DNA (mtDNA) has known associations with cytoplasmic male sterility in numerous gynodioecious plant species and is manifested as petite mutants in experimental yeast lab populations, examples of selfish mtDNA in animals are less common. We analyzed the inheritance and evolution of mitochondrial DNA bearing large heteroplasmic deletions including nad5 gene sequences (nad5 Delta mtDNA), in the nematode Caenorhabditis briggsae. The deletion is widespread in C. briggsae natural populations and is associated with deleterious organismal effects. We studied the inheritance patterns of nad5 Delta mtDNA using eight sets of C. briggsae mutation-accumulation (MA) lines, each initiated from a different natural strain progenitor and bottlenecked as single hermaphrodites across generations. We observed a consistent and strong drive toward higher levels of deletion-bearing molecules in the heteroplasmic pool of mtDNA after ten generations of bottlenecking. Our results demonstrate a uniform transmission bias whereby nad5 Delta mtDNA accumulates to higher levels relative to intact mtDNA in multiple genetically diverse natural strains of C. briggsae. We calculated an average 1% per-generation transmission bias for deletion-bearing mtDNA relative to intact genomes. Our study, coupled with known deleterious phenotypes associated with high deletion levels, shows that nad5 Delta mtDNA are selfish genetic elements that have evolved in natural populations of C. briggsae, offering a powerful new system to study selfish mtDNA dynamics in metazoans.
|URL||<Go to ISI>://WOS:000307045600026|