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J Benzie

Publications and source records attributed to J Benzie.

3 recordsLinked to original sources

The complete sequence of the mitochondrial genome of the crustacean Penaeus monodon: are malacostracan crustaceans more closely related to insects than to branchiopods?

The complete sequence of the mitochondrial genome of the giant tiger prawn, Penaeus monodon (Arthropoda, Crustacea, Malacostraca), is presented. The gene content and gene order are identical to those observed in Drosophila yakuba. The overall AT composition is lower than that observed in the known insect mitochondrial genomes, but higher than that observed in the other two crustaceans for which complete mitochondrial sequence is available. Analysis of the effect of nucleotide bias on codon composition across the Arthropoda reveals a trend with the crustaceans represented showing the lowest proportion of AT-rich codons in mitochondrial protein genes. Phylogenetic analysis among arthropods using concatenated protein-coding sequences provides further support for the possibility that Crustacea are paraphyletic. Furthermore, in contrast to data from the nuclear gene EF1alpha, the first complete sequence of a malacostracan mitochondrial genome supports the possibility that Malacostraca are more closely related to Insecta than to Branchiopoda.

Animals↗

Large mitochondrial DNA differences between morphologically similar Penaeid shrimp.

Sequencing of mtDNA fragments amplified with the polymerase chain reaction is used to examine genetic differences between species of Penaeid shrimp. The data show surprisingly high genetic differences among morphologically and ecologically similar species. Differences at silent sites between subgenera of shrimp are larger than between families of mammals. Between genera, Penaeid shrimp are more divergent than some orders of mammals. Because taxonomic differences are defined on morphological grounds, these results imply that the rates of molecular versus morphological evolution in shrimp are different than in mammals. Perhaps mtDNA evolution is accelerated in shrimp, or perhaps stabilizing selection over a long time period has reduced rates of morphological change. For Penaeid shrimp, morphological similarity can mask large genetic differences.

Amino Acid Sequence↗