Kara Chin et al. (2005) International Worm Meeting "Who needs mitochondrial mtDNA anyway? Fitness effects of the 3.1kb UaDf-5 mtDNA deletion."

Cleonique Deshommes, Aidyl Gonzalez-Serricchio, Craig LaMunyon, Kara Chin

[International Worm Meeting, 2005]

Mitochondrial chromosomes have very little non-coding DNA, and non-mutated chromosomes are generally considered to be associated with increased metabolic fitness. In C. elegans, the UaDf5 mtDNA deletion removes 3.1kb encompassing 11 genes, and yet this deletion can be maternally transmitted for at least 100 generations in a stable heteroplasmic state at all developmental stages (Tsang and Lemire , 2002). Why should a mitochondrial deletion persist? We investigated this question by looking at several measures of metabolism and fitness in relation to the proportion of UaDf-5 deleted mtDNA. Our data support Tsang and Lemires (2002) findings of stable heteroplasmy between wild-type and deleted mtDNA, even though the proportion of deleted mtDNA can vary greatly among siblings and over the course of several generations. We also looked at individual tissues of worms and found no mosaicism among the gut, testes and other tissues for this deletion. We found a positive correlation between the proportion of deleted mtDNA and measures of metabolism (defecation, feeding, and egg-laying rates), indicating that worms bearing this deletion of the mitochondrial chromosome are more fit than wild-type, at least under laboratory conditions.Tsang WY, Lemire BD, 2002. Biochem Cell Biol 80:645-54.