Variable numbers of simple tandem repeats make birds of the order ciconiiformes heteroplasmic in their mitochondrial genomes.
We have analyzed a variable domain of the mitochondrial DNA control region of 18 avian species. Intra-individual length variation was identified and characterized in 15 species. The occurrence of heteroplasmy among species is phylogenetically consistent with a current classification of birds. Polymerase chain reaction amplifications, direct sequencing, and Southern analysis of mitochondrial DNA showed that the heteroplasmy is due to variable numbers of direct repeats in a tandem organization, located in the control region close to the tRNAPhe gene. The tandem repeats consist of short sequence motifs that vary in size from 4 to 32 base pairs between species. Sequence complexity of the repeat motifs was low, with almost exclusively Ts and Gs in the heavy-strand. Extensive variation in the copy number of the repeats was seen both intra-specifically and within individuals. This is the first report of mitochondrial heteroplasmy characterized at the sequence level in birds.
Berg
T
T
Department of Cell Biology, University of Tromsø, Norway.
Moum
T
T
Johansen
S
S
D000818:Animals; D001483:Base Sequence; D001717:Birds / Q000145:classification / Q000235:genetics*; D015139:Blotting, Southern; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D018740:Genetic Heterogeneity; D018598:Minisatellite Repeats; D008969:Molecular Sequence Data; D009245:NADH Dehydrogenase / Q000235:genetics; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012352:RNA, Transfer, Glu / Q000235:genetics; D012360:RNA, Transfer, Phe / Q000737:chemistry* / Q000235:genetics*; D018741:Replication Origin; D012689:Sequence Homology, Nucleic Acid
D004272:DNA, Mitochondrial; D012352:RNA, Transfer, Glu; D012360:RNA, Transfer, Phe; D009245:NADH Dehydrogenase