Organization of the Large Mitochondrial Genome in the Isopod Armadillidium vulgare

Corresponding author: Roland Raimond, UMR CNRS 6556 Génétique et Biologie des Populations de Crustacés, Université de Poitiers, 40 Avenue du Recteur Pineau, F-86022 Poitiers Cedex, France., roland.raimond{at}campus.univ-poitiers.fr (E-mail)

Communicating editor: W. F. EANES

The mitochondrial DNA (mtDNA) in animals is generally a circular molecule of ~15 kb, but there are many exceptions such as linear molecules and larger ones. RFLP studies indicated that the mtDNA in the terrestrial isopod Armadillidium vulgare varied from 20 to 42 kb. This variation depended on the restriction enzyme used, and on the restriction profile generated by a given enzyme. The DNA fragments had characteristic electrophoretic behaviors. Digestions with two endonucleases always generated fewer fragments than expected; denaturation of restriction profiles reduced the size of two bands by half; densitometry indicated that a number of small fragments were present in stoichiometry, which has approximately twice the expected concentration. Finally, hybridization to a 550-bp 16S rDNA probe often revealed two copies of this gene. These results cannot be due to the genetic rearrangements generally invoked to explain large mtDNA. We propose that the large A. vulgare mtDNA is produced by the tripling of a 14-kb monomer with a singular rearrangement: one monomer is linear and the other two form a circular dimer. Densitometry suggested that these two molecular structures were present in different proportions within a single individual. The absence of mutations within the dimers also suggests that replication occurs during the monomer phase.

This article has been cited by other articles:

				S. Tang and B. C. Hyman Mitochondrial Genome Haplotype Hypervariation Within the Isopod Parasitic Nematode Thaumamermis cosgrovei Genetics, June 1, 2007; 176(2): 1139 - 1150. [Abstract] [Full Text] [PDF]

				R. L. Roehrdanz, M. E. Degrugillier, and W. C. Black IV Novel Rearrangements of Arthropod Mitochondrial DNA Detected with Long-PCR: Applications to Arthropod Phylogeny and Evolution Mol. Biol. Evol., June 1, 2002; 19(6): 841 - 849. [Abstract] [Full Text] [PDF]

				D. V. Lavrov, J. L. Boore, and W. M. Brown Complete mtDNA Sequences of Two Millipedes Suggest a New Model for Mitochondrial Gene Rearrangements: Duplication and Nonrandom Loss Mol. Biol. Evol., February 1, 2002; 19(2): 163 - 169. [Abstract] [Full Text] [PDF]

				T. Rigaud, D. Bouchon, C. Souty-Grosset, and R. Raimond Mitochondrial DNA Polymorphism, Sex Ratio Distorters and Population Genetics in the Isopod Armadillidium vulgare Genetics, August 1, 1999; 152(4): 1669 - 1677. [Abstract] [Full Text]