Along with the sequencing technology development and continual enthusiasm of researchers on the mitochondrial genomes, the number of metazoan mitochondrial genomes reported has a tremendous growth in the past decades....Along with the sequencing technology development and continual enthusiasm of researchers on the mitochondrial genomes, the number of metazoan mitochondrial genomes reported has a tremendous growth in the past decades. Phylomitogenomics—reconstruction of phylogenetic relationships based on mitochondrial genomic data—is now possible across large animal groups. Crustaceans in the class Malacostraca display a high diversity of body forms and include large number of ecologically and commercially important species. In this study, comprehensive and systematic analyses of the phylogenetic relationships within Malacostraca were conducted based on 86 mitochondrial genomes available from Gen Bank. Among 86 malacostracan mitochondrial genomes, 54 species have identical major gene arrangement（excluding t RNAs） to pancrustacean ground pattern,including six species from Stomatopoda, three species from Amphipoda, two krill, seven species from Dendrobranchiata（Decapoda）, and 36 species from Pleocyemata（Decapoda）. However, the other 32 mitochondrial genomes reported exhibit major gene rearrangements. Phylogenies based on Bayesian analyses of nucleotide sequences of the protein-coding genes produced a robust tree with 100% posterior probability at almost all nodes. The results indicate that Amphipoda and Isopoda cluster together（Edriophthalma）（BPP=100）.Phylomitogenomic analyses strong support that Euphausiacea is nested within Decapoda, and closely related to Dendrobranchiata, which is also consistent with the evidence from developmental biology. Yet the taxonomic sampling of mitochondrial genome from Malacostraca is very biased to the order Decapoda, with no complete mitochondrial genomes reported from 11 of the 16 orders. Future researches on sequencing the mitochondrial genomes from a wide variety of malacostracans are necessary to further elucidate the phylogeny of this important group of animals. With the increase in mitochondrial genomes available, phylomitogenomics will emerge as an important component in the Tree of Life researches.展开更多
We describe the formation of the major axon pathways in the embryonic central and peripheral nervous systems of the amphipod crustacean Orchestia cavimana Heller,1865 by means of antibody staining against acetylated a...We describe the formation of the major axon pathways in the embryonic central and peripheral nervous systems of the amphipod crustacean Orchestia cavimana Heller,1865 by means of antibody staining against acetylated alphatubulin.The data add to a long list of previous studies of various other aspects of development in Orchestia and provide a basis for future studies of neurogenesis on a deeper cellular and molecular level.Orchestia exhibits a tripartite dorsal brain,which is a characteristic feature of euarthropods.Its anlagen are the first detectable structures in the developing nervous system and can be traced back to distinct neuronal cell clusters in the early embryo.The development of the ventral nervous system proceeds with an anteroposterior gradient of development.In each trunk segment,the longitudinal connectives and the anterior commissure form first,followed by the intersegmental nerve,the posterior commissure and segmental nerves,respectively.A single commissure of a vestigial seventh pleonal segment is found.In the peripheral nervous system we observe a spatial and temporal pattern of leg innervation,which is strikingly similar in both limb types,the uniramous pereopods and the biramous pleopods.A proximal leg nerve splitting distally into two separated nerves probably reflects a general feature of crustaceans.展开更多
基金The National Natural Science Foundation of China under contract Nos 41476146 and 40906067Hong Kong Scholars Program under contract No.XJ2012056+1 种基金China Postdoctoral Science Foundation under contract Nos 2012M510054 and 2012T50218a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Along with the sequencing technology development and continual enthusiasm of researchers on the mitochondrial genomes, the number of metazoan mitochondrial genomes reported has a tremendous growth in the past decades. Phylomitogenomics—reconstruction of phylogenetic relationships based on mitochondrial genomic data—is now possible across large animal groups. Crustaceans in the class Malacostraca display a high diversity of body forms and include large number of ecologically and commercially important species. In this study, comprehensive and systematic analyses of the phylogenetic relationships within Malacostraca were conducted based on 86 mitochondrial genomes available from Gen Bank. Among 86 malacostracan mitochondrial genomes, 54 species have identical major gene arrangement（excluding t RNAs） to pancrustacean ground pattern,including six species from Stomatopoda, three species from Amphipoda, two krill, seven species from Dendrobranchiata（Decapoda）, and 36 species from Pleocyemata（Decapoda）. However, the other 32 mitochondrial genomes reported exhibit major gene rearrangements. Phylogenies based on Bayesian analyses of nucleotide sequences of the protein-coding genes produced a robust tree with 100% posterior probability at almost all nodes. The results indicate that Amphipoda and Isopoda cluster together（Edriophthalma）（BPP=100）.Phylomitogenomic analyses strong support that Euphausiacea is nested within Decapoda, and closely related to Dendrobranchiata, which is also consistent with the evidence from developmental biology. Yet the taxonomic sampling of mitochondrial genome from Malacostraca is very biased to the order Decapoda, with no complete mitochondrial genomes reported from 11 of the 16 orders. Future researches on sequencing the mitochondrial genomes from a wide variety of malacostracans are necessary to further elucidate the phylogeny of this important group of animals. With the increase in mitochondrial genomes available, phylomitogenomics will emerge as an important component in the Tree of Life researches.
基金We thank the plant physiology section at Humboldt University,Berlin for help with the CLSM.We are very grateful to Caterina Biffis,Georg Brenneis and the 2 anonymous reviewers for the helpful advice.We also thank Stephen Rossiter for improving the English.
文摘We describe the formation of the major axon pathways in the embryonic central and peripheral nervous systems of the amphipod crustacean Orchestia cavimana Heller,1865 by means of antibody staining against acetylated alphatubulin.The data add to a long list of previous studies of various other aspects of development in Orchestia and provide a basis for future studies of neurogenesis on a deeper cellular and molecular level.Orchestia exhibits a tripartite dorsal brain,which is a characteristic feature of euarthropods.Its anlagen are the first detectable structures in the developing nervous system and can be traced back to distinct neuronal cell clusters in the early embryo.The development of the ventral nervous system proceeds with an anteroposterior gradient of development.In each trunk segment,the longitudinal connectives and the anterior commissure form first,followed by the intersegmental nerve,the posterior commissure and segmental nerves,respectively.A single commissure of a vestigial seventh pleonal segment is found.In the peripheral nervous system we observe a spatial and temporal pattern of leg innervation,which is strikingly similar in both limb types,the uniramous pereopods and the biramous pleopods.A proximal leg nerve splitting distally into two separated nerves probably reflects a general feature of crustaceans.
