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Mitochondrial DNA polymorphism in black flies (Diptera:Simuliidae)
Abstract
Mitochondrial DNA (mtDNA) polymorphism in black flies was studied. Restriction fragment length polymorphisms among eight black fly species showed clear distinctions among these species. Species showed polymorphism as underrepresented fragments when population homogenates of purified mtDNA were digested with restriction enzymes. In Nebraska, Simulium tuberosum, S. arcticum and S. luggeri are single species with different mitochondrial genotypes present in the same frequencies in successive generations. S. bivittatum and S. piperi are polymorphic species. No polymorphism was detected in mtDNA of S. aureum and S. johannseni, S. vittatum showed extreme polymorphism. Sixteen overwintering populations had a standard genome, ten spring and summer populations had multiple genomes. Biological and cytological evidence support overwintering populations to be IIIL-I sibling, spring and summer populations to be IS-7 and IIIL-I sibling mixtures. A broad geographic survey of 416 individuals of S. vittatum with restriction site analysis showed 15 HindIII genotypes and 4 EcoRI genotypes. S. vittatum characterized by HindIII polymorphism had no relation to siblings identified by chromosomes. Heteroplasmy was also found. There appeared to be no geographic population structure with reference to the different mitochondrial genotypes. Current cytological classification of S. vittatum could neither be accepted nor refute by its mtDNA polymorphism. The heterologous probes of S. vittatum were useful in separating species in the S. jenningsi group and determining restriction maps of S. bivittatum and S. tuberosum. Nucleotide sequence data for 3818-bp of S. vittatum mtDNA was obtained. This included partial or complete nucleotide sequences of 11 protein genes, seven tRNA genes and the large rRNA gene. Comparison of S. vittatum and Drosophila yakuba sequences shoed that gene orders are the same between the two insects; the overall frequency of nucleotide substitutions if 19.1%. S. vittatum is less A + T rich (69.9%) than D. yakuba (73.6%) for all eleven protein genes. Phylogenetic trees derived from two regions of mitochondrial genes were similar. The relative times of divergence among nine black fly species, D. yakuba and Aedes albopictus were estimated. Drosophila, mosquito and black flies appear almost equally divergent.
Subject Area
Molecular biology|Entomology|Genetics
Recommended Citation
Zhu, Xiaolong, "Mitochondrial DNA polymorphism in black flies (Diptera:Simuliidae)" (1991). ETD collection for University of Nebraska-Lincoln. AAI9130817.
https://digitalcommons.unl.edu/dissertations/AAI9130817