Vida JT et al. (1995) International C. elegans Meeting "MODE AND TEMPO OF MOLECULAR EVOLUTION IN FOUR CAENORHABDITIS SPECIES"

Nunn GB, Frisse LM, Vida JT, Thomas WK

[International C. elegans Meeting, 1995]

Up to this point, a major problem in investigating the molecular evolution of C. elegans and three of its commonly studied relatives (C. briggsae, C. remanei, and C. vulgaris), is the lack of a closely related taxa to use as an outgroup. We have completely sequenced a 2.2kb cDNA encoding fragment ofthe large subunit of RNA polymerase II, as well as the genes for the large subunit (26s) of ribosomal RNA and the rnitochondrial cytochrome oxidase II for C. elegans, C. briggsae, C. remanei, C. vulgaris, and an undescribed new species (PS1010). Analysis of the data indicates PS1010 is a closely related sister taxa to the Caenorhabditis. Outgroup rooting of the Caenorhabditis with PS1010 irnproves the resolution of the phylogenetic relationships among the Caenorhabditis species. In addition, rooting with the closely related PS1010 improves the ability to compare rates and patterns of evolution in the three genes sequenced.

Hatakeyama S et al. (1999) Oncogene "JTB: a novel membrane protein gene at 1q21 rearranged in a jumping translocation."

Hatakeyama S, Omine M, Osawa M, Ishikawa F

[Oncogene, 1999]

1q21 is frequently involved in different types of translocation in many types of cancers. Jumping translocation (JT) is an unbalanced translocation that comprises amplified chromosomal segments jumping to various telomeres. In this study, we identified a novel gene human JTB (Jumping Translocation Breakpoint) at 1q21, which fused with the telomeric repeats of acceptor telomeres in a case of JT. hJTB (human JTB) encodes a trans-membrane protein that is highly conserved among divergent eukaryotic species. JT results in a hJTB truncation, which potentially produces an hJTB product devoid of the trans-membrane domain. hJTB is located in a gene-rich region at 1q21, called EDC (Epidermal Differentiation Complex). This is the first report identifying the gene involved in unbalanced translocations at 1q21.

Frisse LM et al. (1995) International C. elegans Meeting "EVALUATION OF A MOLECULAR DATABASE FOR NEMATODE TAXONOMY"

Frisse LM, Vida JT, Thomas WK

[International C. elegans Meeting, 1995]

A large number of nematode species remain to be identified. To overcome this problem a common set of taxonomic characters is needed. Nematode species exhibit great diversity at the molecular level. This molecular variation may be useful as a taxonomic tool. Recent technical advances, in particular the advent of the polymerase chain reaction and automated sequencing, have made the generation of sequences for large numbers of individuals a realistic goal. In an attempt to set up a molecular database, we have chosen the D3 expansion segment of the gene for the largest subunit of ribosomal RNA as our molecular species tag. This segment amplifies in a wide range of nematode taxa, can be sequenced from all developmental stages, and provides unambiguous character sets that require no subjective evaluation. When a complete sequence is obtained for each new sample, it is compared to existing sequences for identification. If the sequence represents a new sample it is added to the main database. The existing database contains over 80 sequences and is being evaluated for its usefulness as a taxonomic tool.

Frisse LM et al. (1997) International C. elegans Meeting "IDENTIFICATION OF MISMATCH REPAIR GENES IN C. ELEGANS"

Thomas WK, Lam KM, Vida JT, Frisse LM

[International C. elegans Meeting, 1997]

The MRS is critical for maintenance of genome stability and faithful genetic inheritance. Currently, Saccharomyces cerevisiae is the only eukaryotic system in which homologs of mutS and mutL have been studied thoroughly. MutS and MutL homologs of yeast MRS suppress error rates during replication and control recombination during meiosis. Deficiencies in MRS homologs of yeast display mismatch repair deficiency, microsatellite instability, and meiotic nondisjuction. We have identified four putative Caenorahbditis elegans MRS homologs by searching the C. elegans genome database using functionally characterized yeast MutS and MutL homologs as query sequences. The nematode homologs have been compared with homologs from bacteria, yeast, and other organisms in order to develop a phylogenetic hypothesis of relationships. Based on the relationships, we have identified and proposed functions for these genes. mlh-1, a homolog to yeast MLH1, and msh-2, a homolog to yeast MSH-2, may both be directly involved in mismatch repair. msh-4, a homolog to yeast MSH4, and msh-5, a homolog to yeast MSH5, are probably both involved in meitic recombination.

Thomas WK et al. (1995) International C. elegans Meeting "AN EVOLUTIONARY FRAMEWORK FOR SOME RELATIVES OF C. ELEGANS"

Frisse LM, Baldwin JG, Thomas WK, Vida JT

[International C. elegans Meeting, 1995]

The evolutionary interpretation of developmental differences requires a framework in the form of a phylogenetic hypothesis. Such a hypothesis allows for the assignment of direction of change and the understanding of phenomena such as shared characteristics. In conjunction with the comparative developmental studies of the nematode vulva by Somrner, Stemberg, and others; we have begun a phylogenetic analysis of key nematode species representing cntical changes in vulval development. The species include Mesorhabdidtis sp., Teratorhabditis palmarum, Cruznema tripartitum, C. elegans and an undescribed new species (PS-1010). Current phylogenetic hypotheses on the relationship among major lineages in the Rhabditidae are based on relatively few useful morphological characteristics. In order to develop a phylogenetic hypothesis independant of the developmental comparsions and based on a large number of characters, we have used coding portions of the largest subunit of RNA polyrnerase II and the large subunit of rRNA. Three observations are particularly noteworthy. 1) The branching order among the five taxa is resolved significantly. 2) A morphologically distinct taxa, PS-1010, is the sister taxa to the Caenorhabditis. 3) The divergence levels among nematode taxa from the same superfamily are as high as those found between major metazoan lineages.

Baldwin JG et al. (1997) Mol Phylogenet Evol "An evolutionary framework for the study of developmental evolution in a set of nematodes related to Caenorhabditis elegans."

Thomas WK, Frisse LM, Eddleman CD, Baldwin JG, Vida JT

[Mol Phylogenet Evol, 1997]

Nematodes are known to be a useful system for studies of comparative development. Here we perform a molecular phylogenetic analysis to allow for the independent interpretation of the developmental and morphological changes observed among a selected set of nematode species. Our molecular phylogenetic analysis is based on coding regions of the genes for RNA polymerase II, the small subunit rRNA and an expansion segment of the large subunit rRNA. Sequences were compared from five species in the family (Rhabditidae) that includes the developmental model organism Caenorhabditis elegans and from an outgroup taxon Aduncospiculum halicti (Diplogasterina). The phylogenetic analysis does not support the monophyly of the subfamily Mesorhabditinae and identifies the unnamed strain PS1010 as a sister taxon of C. elegans despite its morphologically divergent buccal capsule. On the basis of the inferred framework, we can begin to interpret the evolution of vulval development and of morphological differences among these nematode species.

Lam KM et al. (1997) International C. elegans Meeting "THE ROLE OF MALES IN C. ELEGANS"

Frisse LM, Vida JT, Shores ML, Raw HL, Lam KM, Thomas WK

[International C. elegans Meeting, 1997]

Wild type strains of Caenorhabditis elegans are primarily self-fertilizing hermaphrodites but also produce functional males by meiotic non-disjunction. While it is presumed that males occur in nature, we have no evidence that males "perform" in nature. The goal of this study is to investigate whether or not C. elegans males participate in effective outbreeding during the evolution of this species or whether C. elegans evolves as a set of non-interbreeding clonal lineages. To evaluate the evolutionary contributions of outcrossing by males, we first developed an evolutionary history of C. elegans mitochondrial DNA, which represents a maternal clonal history. We then compared the mitochondrial phylogeny with one based on nuclear markers, including Tc1 and microsatellite loci. If inheritance was strictly clonal, the resulting phylogenies should be identical. However, if males play an effective role in genome evolution, the mitochondrial and nuclear phylogenies should be different. Analysis of 28 independently isolated C. elegans strains resulted in mitochondrial and nuclear phylogenies that were almost completely congruent. Nevertheless, strains with differences in phylogenetic placement based on mitochondrial and nuclear variation were identified. These exceptions represent evidence that males play a role in the evolution of C. elegans.

Baldwin JG et al. (1997) Canadian Journal of Zoology "The buccal capsule of Aduncospiculum halicti (Nemata: Diplogasterina): an ultrastructural and molecular phylogenetic study."

Vida JT, Williams DS, Baldwin JG, Eddleman CD, Giblin-Davis RM, Thomas WK

[Canadian Journal of Zoology, 1997]

The buccal capsule of Aduncospiculum halicti (Diplogasterina) is compared with that of Zeldia punctata (Cephalobina) and Caenorhabditis elegans (Rhabditina). Characters are mapped on an independent DNA-based phylogenetic tree (inferred from RNA polymerase II and rDNA sequences) to test evolutionary hypotheses. Irrespective of dimorphism, the buccal capsule wall of A. halicti consists of an anterior to posterior series of six cuticular structures classically termed rhabdions. These are defined according to their internal differentiations, discontinuities in profiles, and underlying tissues. Homologies of rhabdions 1 and 2 in A. halicti are proposed on the basis of position and association with adjacent tissues, consistent with those of Cephalobina and Rhabditina. Rhabdion 3 is associated with radial epithelial cells as is the mesorhabdion in C. elegans; this contrasts with Z. punctata, where a rhabdion in a similar position is associated with radial muscle cells. Dorsal and subventral teeth in A. halicti comprise rhabdions 4 and 5; this may be homologous with a corresponding region in Z. punctata but contrasts with C. elegans, where the corresponding region consists of a single metarhabdion. These characters, when mapped on the sequence-based tree, suggest that A. halicti and Diplogasterina share with C. elegans and other Rhabditina derived characters, including a mesorhabdion associated with epithelial cells, but retain some apparently primitive features shared with Cephalobina.

Blaxter ML et al. (1997) International C. elegans Meeting "PUTTING C. ELEGANS IN ITS PLACE: A MOLECULAR PHYLOGENY OF THE PHYLUM NEMATODA"

Dorris M, Thomas WK, Scheldeman P, Garey JR, Vanfleteren JR, Liu LX, DeLey P, Vida JT, Blaxter ML, Frisse LM

[International C. elegans Meeting, 1997]

The Phylum Nematoda includes four of every five metazoan animals on the planet. Nematodes are important because of their diversity, ecological significance and impact as parasites of plants, humans and other animals. Morphological studies have failed to provide a unifying phylogenetic framework due to a lack of informative fossils and the limitations of light-microscopy. We present here a phylogenetic analysis using small subunit (SSU) ribosomal DNA sequences from a wide range of nematode taxa. For the first time animal-parasitic, plant-parasitic and free-living taxa can be compared using the same metric. We pinpoint the multiple origins of parasitism within the phylum, identify candidate research models from free-living sister taxa of parasitic clades, and place into context the metazoan research model Caenorhabditis elegans. Our results also suggest that convergent evolution has occurred more frequently in nematodes than hitherto assumed, and that classification will need significant changes.

Filingeri D (2015) J Neurophysiol "Humidity sensation, cockroaches, worms, and humans: are common sensory mechanisms for hygrosensation shared across species?"

Filingeri D

[J Neurophysiol, 2015]

Although the ability to detect humidity (i.e., hygrosensation) represents an important sensory attribute in many animal species (including humans), the neurophysiological and molecular bases of such sensory ability remain largely unknown in many animals. Recently, Russell and colleagues (Russell J, Vidal-Gadea AG, Makay A, Lanam C, Pierce-Shimomura JT. Proc Natl Acad Sci USA 111: 8269-8274, 2014) provided for the first time neuromolecular evidence for the sensory integration of thermal and mechanical sensory cues which underpin the hygrosensation strategy of an animal (i.e., the free-living roundworm Caenorhabditis elegans) that lacks specific sensory organs for humidity detection (i.e., hygroreceptors). Due to the remarkable similarities in the hygrosensation transduction mechanisms used by hygroreceptor-provided (e.g., insects) and hygroreceptor-lacking species (e.g., roundworms and humans), the findings of Russell et al. highlight potentially universal mechanisms for humidity detection that could be shared across a wide range of species, including humans.