H M Robertson

..This has allowed us the initial investigation of chemoreceptor genes in an aquatic invertebrate, and to begin the study of chemoreceptor evolution across the arthropod phylum...

..Animal genomes contain families of genes encoding chemoreceptors that mediate taste, olfaction, and pheromone responses. The size and diversity of these families reflect the biology of chemoperception in specific species...

..As with the odorant receptors, one receptor is expressed per sensory neuron, each class of which projects to discrete regions of the brain, allowing a combinatorial coding system for specific recognition of ligands...

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..At least two of these species can detect carbon dioxide, suggesting that they evolved other means to do so...

..These might be viewed as a discrete family of transposons within the IS630-Tc1-mariner superfamily with a distinctive D,D37D catalytic motif, and another small divergent D,D41D clade is recognized as their sister group of transposons...

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..Together these observations provide insight into the evolutionary dynamics of this compact animal genome...

..Altogether, these patterns of molecular evolution suggest that this is an ancient superfamily of chemoreceptors, probably dating back at least to the origin of the arthropods...

..Single homologs are present in basal deuterostome and insect genomes, including Drosophila, and three trypanosomatid protists. VKOR is therefore an ancient gene/protein that can be studied in the Drosophila model system...

..They have 1-2 kb of TTAGGG telomeric repeats, which are preceded by a subtelomeric region of 1.5-13 kb. Unlike subtelomeric regions in most animals examined, these subtelomeric regions are unique to each telomere...

..As expected from the presence of canonical TTAGG telomeric repeats, we identified a candidate telomerase gene in the bee, as well as the silkmoth Bombyx mori and the flour beetle Tribolium castaneum...

..Nine duplicate gene models on chromosomes 15 and 16 were made redundant, while another 15 gene models were improved, most spectacularly the MAD (MAX dimerization protein) gene which extends across 11 scaffolds for at least 400 kb...

..Thus large random deletions presumably balance the rapid proliferation of genes and their degeneration into pseudogenes, while gene movement within and between chromosomes keeps these nematode genomes in flux...

..Exon 3 is efficiently spliced into position in the mature transcript. This unusual gene arrangement is ancient within mosquitoes, being shared by Aedes aegypti and Culex pipiens...

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..Thus, this transposon had a considerable insertional mutagenic effect on past primate genomes...

..These copies provide multiple independent datasets for evaluating the pattern of neutral evolution in the human genome, for example, they confirm that most indels are very short and that deletions are twice as common as insertions...

..Bmmar1 considerably increases the known diversity of this widespread family of transposons. A new naming system is proposed for members of the family...

..wustl.edu/Pfam); alignments of all translations are available at http://cshl.org/gr; alignments of the genes are available from the author at hughrobe@uiuc.edu]..

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..These Grs might therefore mediate food choice and avoidance as well as oviposition site preference...

..These results suggest that BmOr19 and 30 may detect odours critical to female behaviour, such as oviposition cues or male-produced courtship pheromones...

..Therefore the mariner element is an excellent candidate for development of genetic transformation systems for non-drosophilid insects, and possibly other arthropods...

..The widespread but sporadic distribution of mariner elements suggests they are excellent candidates for development as transformation vectors for non-drosophilids...

..Ectopic muscle expression of either isoform beyond the time it normally ceases leads to paralysis and lethality. Together, our results offer an example of well-conserved alternative splicing increasing cellular diversity in metazoans...

..Twenty other invertebrates representing the major phyla did not appear to have mariners of these kinds in their genomes...

..These experiments indicate that in D. simulans and D. mauritiana expression of the cytoplasmic incompatibility phenotype is determined by the bacterial strain and that D. mauritiana harbors a neutral strain of Wolbachia...

..To maximize transcript diversity we created and sequenced separate libraries from larvae, pupae, adult heads, and headless adult bodies...

..This rich patchwork of distinct domains probably exerts multiple effects on a variety of cell behaviors associated with the complex phenomenon of epithelial morphogenesis...

..These data suggest that a threshold level of infection is required for normal expression of CI and that host factors help determine the density of the symbiont in the host...

..We also apply the framework to find motifs associated with socially regulated gene sets in the honeybee, Apis mellifera, using comparisons with Nasonia, a solitary species, to identify honeybee-specific associations...

..In particular, most instances of alternative splicing in orthologous loci appear to have evolved after the culicine-anopheline split +/-150 million years ago...

..The sequence data described in this paper have been submitted to Genbank data library under accession nos. BI502708-BI517278. The sequences are also available at http://titan.biotec.uiuc.edu/bee/honeybee_project.htm.]..

..These elements coincide with those described recently as Tigger1 and Tigger2, respectively. These transposons appear to have been active 80-90 Myr ago in the genome of an early primate or primate ancestor...

..We examined the evolution of these SRs within the 12 available Drosophila genome sequences, as well as three mosquito, two moth, and beetle, bee, and wasp genome sequences...

..Combinations of the restriction enzymes DdeI, HinfI and Sau3AI provided diagnostic bands for identification of the ten species from three families of Diptera (Calliphoridae, Muscidae and Sarcophagidae)...

..This is the first tephritid OR discovered that might recognize a specific odorant. Other olfactory genes recovered included odorant binding proteins, chemosensory proteins, and putative odorant degrading enzymes...

..Insect pteropsin might be orthologous to a ciliary opsin recently described from the annelid Platynereis, and therefore represents the presence of this vertebrate-like light-detecting system in insects...

..Three puparia collected in 1997 produced double PCR bands that corresponded to PCR band sizes of Muscidifurax spp. and Spalangia sp., possibly indicating multiple parasitism or hyperparasitism...

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..1 subsitutions/site. This high rate of DNA deletion may explain the compact nature of the nematode genome...

..The honey bee provides an opportunity to study the roles of methylation in social contexts...

..Given that Wolbachia infections are relatively common in insects, it is likely that other insect hybrid zones may be influenced by infections with Wolbachia...

..Unlike P cytotype, however, there was no reciprocal cross effect in the inheritance of repression...

..A noticeable bias in target site usage suggests a preference for insertion into bent or bendable DNA sequences rather than any specific nucleotide sequences beyond the TA target site...

..sexta antennae. RT-PCR and qRT-PCR show that this receptor is expressed only in male and female antennae. These are the first ORs, including a putative pheromone receptor, to be described from M. sexta...

..Abundant expression of Ms-golgin80 in neuroblasts and ganglion mother cells and its reduced expression in the neuronal progeny of these cells suggest that this protein may be involved in the maintenance of the proliferative state...

..We did not observe any responses of the other three Ors to any of the eight QRP pheromone components, suggesting 9-ODA is the only QRP component that also acts as a long-distance sex pheromone...

..These odors will be used in future in vitro studies to determine whether they activate larval-specific odorant receptors...

..Examples of lineage-specific gene expansions were observed as well as a single instance of unusually high sequence conservation...

..We interpret these results as indicating that the srz family is under positive selection, probably driven by ligand binding...

..We propose that Ncad isoforms do not form an adhesion code; rather, they provide permissive adhesion between R7 growth cones and their temporary targets...

..Systemic RNA interference in T. castaneum functions differently from that in Caenorhabditis elegans, but nevertheless offers similar power for the elucidation of gene function and identification of targets for selective insect control...

..The substantial number of Ors poses the question of why Tribolium has such a large olfactory receptor repertoire, and underlines the need for more studies of the natural history of this species...

..These findings illustrate a previously unappreciated diversity of insect clockwork and raise critical questions concerning the evolution and functional significance of species-specific variation in molecular clockwork...

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..It will also reveal how occasionally particular copies of transposons can become integral parts of their host genetic complements. ..

..This work will also contribute to our overall understanding of the molecular basis of chemoreception in insects and other animals. ..