Evidence from 12
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            Ribosomal RNA Sequences that Onychophorans Are Modified Arthropods

Ballard, J. William O.; Olsen, Gary J.; Faith, Daniel P.; Odgers, W.A.; Rowell, David M.; Atkinson, Philip W.

doi:10.1126/science.1455227

Cited by 236 publications

(133 citation statements)

References 20 publications

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“…The presence of an arthropod-type hemocyanin in the Onychophora, which is absent in other animal phyla, confirms this assumption. Molecular phylogenetic studies tend to agree on the view that the Onychophora are allied with the Euarthropoda but generally do not resolve the exact position of this taxon (27)(28)(29). Phylogenetic reconstruction of the evolution of arthropod hemocyanins using the phenoloxidases as the outgroup results in a robust tree, in which the main nodes are well supported in both neighbor-joining and maximum likelihood analyses (Fig.…”

Section: Discussionmentioning

confidence: 79%

A hemocyanin from the Onychophora and the emergence of respiratory proteins

Kusche

Ruhberg

Burmester

2002

Proc. Natl. Acad. Sci. U.S.A.

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The velvet worms (Onychophora) are considered living fossils and are closely related to the Euarthropoda. Onychophora possess a tracheal system for respiratory function, but oxygen-transport proteins have been considered unnecessary. Here, we show that the hemolymph of the Epiperipatus sp. (Onychophora: Peripatidae) contains an arthropod-type hemocyanin, demonstrating that such protein exists outside the Euarthropoda. Thus, the evolution of oxygen carriers preceded the divergence of the Onychophora and Euarthropoda and was most likely linked to the evolution of an efficient circulatory system in a low-oxygen environment. The cDNA of the Epiperipatus hemocyanin subunit comprises 2,287 bp and encodes for a protein of 641 aa (73.6 kDa). Phylogenetic analyses of the arthropod hemocyanin sequences show that the Onychophora form a robust sister-group of the Euarthropoda, whereas the monophyly of the Tracheata is not supported.

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Section: Discussionmentioning

confidence: 79%

A hemocyanin from the Onychophora and the emergence of respiratory proteins

Kusche

Ruhberg

Burmester

2002

Proc. Natl. Acad. Sci. U.S.A.

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“…A combined phylogenetic analysis, using ribosomal and nuclear protein coding genes, as well as mitochondrial genes, also places the onychophorans as a clade distinct from the Euarthropoda (Giribet et al 2001), a conclusion similarly reached by Regier et al (2005), by Mallatt et al (2004) using 28S and 18S rRNA gene sequences and by Edgecombe et al (2000) from histone H3 and U2 snRNA sequences. On the other hand, a study based on 12S ribosomal RNA sequences (Ballard et al 1992) includes Onychophora within the Euarthropoda, placing them as a sister group to the chelicerates, as does the present analysis using neural characters. The question remains whether neuroanatomical features here are sufficient to propose that the Onychophora are related to the chelicerates despite the many primitive features of the onychophoran body plan, including the paired protocerebral antennae, recently shown to be modified legs (Mayer & Koch 2005).…”

Section: Evolutionary Implicationsmentioning

confidence: 99%

Arthropod phylogeny: onychophoran brain organization suggests an archaic relationship with a chelicerate stem lineage

et al. 2006

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Neuroanatomical studies have demonstrated that the architecture and organization among neuropils are highly conserved within any order of arthropods. The shapes of nerve cells and their neuropilar arrangements provide robust characters for phylogenetic analyses. Such analyses so far have agreed with molecular phylogenies in demonstrating that entomostracansCmalacostracans belong to a clade (Tetraconata) that includes the hexapods. However, relationships among what are considered to be paraphyletic groups or among the stem arthropods have not yet been satisfactorily resolved. The present parsimony analyses of independent neuroarchitectural characters from 27 arthropods and lobopods demonstrate relationships that are congruent with phylogenies derived from molecular studies, except for the status of the Onychophora. The present account describes the brain of the onychophoran Euperipatoides rowelli, demonstrating that the structure and arrangements of its neurons, cerebral neuropils and sensory centres are distinct from arrangements in the brains of mandibulates. Neuroanatomical evidence suggests that the organization of the onychophoran brain is similar to that of the brains of chelicerates.

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“…The value of the same for 12S revealed to be higher than the other genes. Usually the 12SrRNA region is highly conserved (Ballard et al, 1992) and 16S is more variable than 12S (Hwang & Kim, 1999). Variation is extremely low at the 3'half of the molecule but it is also observed that the third domain of 12S is A+T rich and phylogenetically informative (Simon et al, 1994).…”

Section: Sequence Divergence For Various Markersmentioning

confidence: 99%

Molecular phylogeny of commercially important lobster species from Indian coast inferred from mitochondrial and nuclear DNA sequences

Jeena

Gopalakrishnan

Radhakrishnan

et al. 2015

Mitochondrial DNA Part A

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Lobsters constitute low-volume high-value crustacean fishery resource along Indian coast. For the conservation and management of this declining resource, accurate identification of species and larvae is essential. The objectives of this work were to generate species-specific molecular signatures of 11 commercially important species of lobsters of families Palinuridae and Scyllaridae and to reconstruct a phylogeny to clarify the evolutionary relationships among genera and species included in this study. Partial sequences were generated for all the candidate species from sampling sites along the Indian coast using markers like Cytochrome oxidase I (COI), 16SrRNA, 12SrRNA, and 18SrRNA genes, and analyzed. The genetic identities of widely distributed Thenus species along the Indian coast to be Thenus unimaculatus and the sub-species of Panulirus homarus to be P. homarus homarus were confirmed. Phylogeny reconstruction using the individual gene and concatenated mtDNA data set were carried out. The overall results suggested independent monophyly of Scyllaridae and Stridentes of Palinuridae. The interspecific divergence was found to be highest for the 12SrRNA compared with other genes. Significant incongruence between mtDNA and nuclear 18SrRNA gene tree topologies was observed. The results hinted an earlier origin for Palinuridae compared with Scyllaridae. The DNA sequence data generated from this study will aid in the correct identification of lobster larvae and will find application in research related to larval transport and distribution.

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Evidence from 12 S Ribosomal RNA Sequences that Onychophorans Are Modified Arthropods

Cited by 236 publications

References 20 publications

A hemocyanin from the Onychophora and the emergence of respiratory proteins

A hemocyanin from the Onychophora and the emergence of respiratory proteins

Arthropod phylogeny: onychophoran brain organization suggests an archaic relationship with a chelicerate stem lineage

Molecular phylogeny of commercially important lobster species from Indian coast inferred from mitochondrial and nuclear DNA sequences

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