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The red flour beetle, Tribolium castaneum (Herbst), is primarily found associated with human structures such as wheat and rice mills. Such structures are predicted to be spatially isolated resource patches with frequent population bottlenecks that should influence their genetic structure. Genetic diversity and differentiation among nine populations of T. castaneum collected from wheat and rice mills (ranging from ST values = 0.018-0.149), genetic distance was not significantly correlated with geographic distance. Correct assignment to the source population was successful for only 56% of individuals collected. Further analyses confirmed the occurrence of recent genetic bottlenecks in five out of nine populations. These results provide evidence that populations of T. castaneum collected from mills show spatial genetic structure, but the poor ability to assign individuals to source populations and lack of isolation by distance suggest greater levels of gene flow than predicted originally. [ABSTRACT FROM AUTHOR]

The article discusses a study to determine the potential insecticide targets of the western corn rootworm, Diabrotica virgifera virgifera (D.v.v) through ribonucleic acid interference (RNAi). It is stated that Coleopteran model, Tribolium castaneum was used to identify the RNAi phenotypes because the silencing of both laccase 2 (D.v.v.Lac2) and chitin synthase 2 (D.v.v.CHS2) is systemic in both Tribolium and D.v.v. It further demonstrates the importance of gene silencing in D.v.v.

Examines a genetic map based on randomly amplified polymorphic DNA (RAPD) of Tribolium castaneum. Efficiency of RAPD mapping; Conversion of RAPD to sequence-tagged site markers; Identification of single-strand conformational polymorphisms; RAPD map as tool for genomics; Correlation between sex chromosomes and linkage group.

Uses population genetic methods to describe the expected population dynamics of the selfish-gene chromosomal factor, maternal-effect dominant embryonic arrest (Medea) of the flour beetle. Medea factors; Rate of spread; Deleterious effects of Medea on fecundity; Possibility of stable interior polymorphism; Degree of dominance as factor in location of interior equilibrium.

Presents a study in which a lethal mutation of the homeotic Abdominal gene of the red flour beetle, Tribolium castaneum, was isolated. Sequence analysis carried out to indicate that this retrotransposon, called Woot, is member of gypsy family of mobile elements; Number of copies harbored by Woot per genome; Inclusion of open reading frames (ORFs) in internal region of Woot.

In Drosophila melanogaster, each of the three paralogous ABC transporters, White, Scarlet and Brown, is required for normal pigmentation of the compound eye. We have cloned the three orthologous genes from the beetle Tribolium castaneum. Conceptual translations of Tribolium white (Tcw), scarlet (Tcst), and brown (Tcbw) are 51, 48, and 32% identical to their respective Drosophila counterparts. We have identified loss-of-eye-pigment strains that bear mutations in Tcw and Tcst: the Tcw gene in the ivory (i) strain carries a single-base transversion, which leads to an E → D amino-acid substitution in the highly conserved Walker B motif, while the Tcst gene in the pearl (p) strain has a deletion resulting in incorporation of a premature stop codon. In light of these findings, the mutant strains i and p are herein renamed whiteivory (wi) and scarletpearl (stp), respectively. In addition, RNA inhibition of Tcw and Tcst recapitulates the mutant phenotypes, confirming the roles of these genes in normal eye pigmentation, while RNA interference of Tcbw provides further evidence that it has no role in eye pigmentation in Tribolium. We also consider the evolutionary implications of our findings. [ABSTRACT FROM AUTHOR]

In insects, the boundary between the embryonic head and thorax is formed by the dorsal ridge, a fused structure composed of portions of the maxillary and labial segments. However, the mechanisms that promote development of this unusual structure remain a mystery. In Drosophila, mutations in the Hox genes Sex combs reduced and Deformed have been reported to cause abnormal dorsal ridge formation, but the significance of these abnormalities is not clear. We have identified three mutant allele classes of Cephalothorax, the Tribolium castaneum (red flour beetle) ortholog of Sex combs reduced, each of which has a different effect on dorsal ridge development. By using Engrailed expression to monitor dorsal ridge development in these mutants, we demonstrate that Cephalothorax promotes the fusion and subsequent dorsolateral extension of the maxillary and labial Engrailed stripes (posterior compartments) during dorsal ridge formation. Molecular and genetic analysis of these alleles indicates that the N terminus of Cephalothorax is important for the fusion step, but is dispensable for Engrailed stripe extension. Thus, we find that specific regions of Cephalothorax are required for discrete steps in dorsal ridge formation. [ABSTRACT FROM AUTHOR]

A genetic linkage map was constructed in a backcross family of the red flour beetle, Tribolium castaneum, based largely on sequences from bacterial artificial chromosome (BAC) ends and untranslated regions from random cDNA's. In most cases, dimoq0hisms were detected using heteroduplex or single-strand conformational polymorphism analysis after specific PCR amplification. The map incorporates a total of 424 markers, including 190 BACs and 165 cDNA's, as well as 69 genes, transposon insertion sites, sequence-tagged sites, microsatellites, and amplified fragment-length polymorphisms. Mapped loci are distributed along 571 cM, spanning all 10 linkage groups at an average marker separation of 1.3 cM. This genetic map provides a framework for positional cloning and a scaffold for integration of the emerging physical map and genome sequence assembly. The map and corresponding sequences can be accessed through BeetleBase (http://www.bioinforrnatics.ksu.edu/BeetleBase/). [ABSTRACT FROM AUTHOR]

Studies the cloning and characterization of the Tribolium castaneum eye-color genes encoding tryptophan oxygenase and kynurenine 3-monooxygenase. Wild-type strains; Degenerate polymerase chain reaction; Isolation of cDNA and genomic clones; DNA sequencing and analysis.

Examines the role Hox gene expression in the morphological evolution of insects. Determination of embryonic labial development; Dependence of labium identity on homeotic genes; Establishment on gnathal segment identities.