Tempo and mode of sequence evolution in mitochondrial DNA of HawaiianDrosophila
- 228 Downloads
Sequence comparisons were made for up to 667 bp of DNA cloned from 14 kinds of HawaiianDrosophila and five other dipteran species. These sequences include parts of the genes for NADH dehydrogenase (subunits 1, 2, and 5) and rRNA (from the large ribosomal subunit). Because the times of divergence among these species are known approximately, the sequence comparisons give insight into the evolutionary dynamics of this molecule. Transitions account for nearly all of the differences between sequences that have diverged by less than 2%; for these sequences the mean rate of divergence appears to be about 2%/Myr. In comparisons involving greater divergence times and greater sequence divergence, relatively more of the sequence differences are due to transversions. Specifically, the fraction of these differences that are counted as transversions rises from an initial value of less than 0.1 to a plateau value of nearly 0.6. The time required to reach half of the plateau value, about 10 Myr, is similar to that for mammalian mtDNA. The mtDNAs of flies and mammals are also alike in the shape of the curve relating the percentage of positions at which there are differences in protein-coding regions to the time of divergence. For both groups of animals, the curve has a steep initial slope ascribable to fast accumulation of synonymous substitutions and a shallow final slope resulting from the slow accumulation of substitutions causing amino acid replacements. However, the percentage of all sites that can experience a high rate of substitution appears to be only about 8% for fly mtDNA compared to about 20% for mammalian mtDNA. The low percentage of hypervariable sites may be a consequence of a functional constraint associated with the low content of guanine and cytosine in fly mtDNA.
Key wordsDideoxy sequencing Molecular clock Transitions Transversions Biased base composition NADH dehydrogenase Ribosomal RNA genes Phylogenetic tree Functional constraint Mosquito Insects
DNA encoding rRNA
Unable to display preview. Download preview PDF.
- Brown GG, Simpson MV (1982) Novel features of animal mtDNA evolution as shown by sequences of two rat cytochrome oxidase subunit II genes. Proc Natl Acad Sci USA 79:3246–3250Google Scholar
- Brown WM (1983) Evolution of animal mitochondrial DNA. In: Nei M, Koehn RK (eds) Evolution of genes and proteins. Sinauer, Sunderland MA, pp 62–88Google Scholar
- Brown WM (1985) The mitochondrial genome of animals. In: MacIntyre RJ (ed) Molecular evolutionary genetics. Plenum, New York, pp 95–130Google Scholar
- Carson HL, Hardy DE, Spieth HT, Stone WS (1970) The evolutionary biology of the Hawaiian Drosophilidae. In: Hecht MK, Steere WC (eds) Essays in evolution and genetics in honor of Theodosius Dobzhansky. Appleton-Century-Crofts, New York, pp 437–543Google Scholar
- Hennig W (1973) Diptera (Zweiflüger). In: Kükenthal W (ed) Handbuch der Zoologie IV:2:2:31. Arthropoda, Insecta, ed 2. W de Gruyter, Berlin, pp 1–337Google Scholar
- Johnson WE, Carson HL, Kaneshiro KY, Steiner WWM, Cooper MM (1975) Genetic variation in Hawaiian Drosophila II. Allozymic differentiation in theD. planitibia subgroup. In: Markert CL (ed) Isozymes IV: genetics and evolution. Academic Press, New York, pp 563–584Google Scholar
- Jukes TH (1982) Silent nucleotide substitutions in evolution. Presented at the Meeting of the Society for the Study of Evolution and The American Society of Naturalists, June 23, 1982, Stony Brook NYGoogle Scholar
- Swofford DL (1985) Phylogenetic analysis using parsimony (PAUP), version 2.4. Illinois Natural History Survey, Champaign ILGoogle Scholar
- Wilson AC, Cann RL, Carr SM, George M, Gyllensten UB, Helm-Bychowski KM, Higuchi RG, Palumbi SR, Prager EM, Sage RD, Stoneking M (1985) Mitochondrial DNA and two perspectives on evolutionary genetics, Biol J Linn Soc 26:375–400Google Scholar