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The red flour beetle, Tribolium castaneum, is a common pest, which has become an important model study organism, especially in genetic, ecological and evolutionary research. Although almost all studies on this species have been conducted using established laboratory strains, very little is known about the loss of genetic diversity within the strains and genetic divergence between different laboratory stocks. In this study, five long-term laboratory strains and one wild strain were examined for genetic variation at 12 microsatellite loci, which were designed using publicly available sequences. One of the laboratory strains is resistant to phosphine and one to organophosphorous insecticides. All strains had significant amounts of molecular variation, but genetic diversity in the laboratory strains was lower than in the wild-derived strain used as control. We observed significant molecular divergence among the strains, however, the relationship between them reflected resistance status rather than geographic origins. We found no evidence for recent bottlenecks, but the wild-derived population showed signs of demographic expansion. A novel multivariate method, multiple co-inertia analysis, revealed that the two loci contributing most to the divergence between the resistant strains were located on the eighth chromosome, near genes associated with insecticide resistance. [ABSTRACT FROM AUTHOR]

Six microsatellite DNA loci were isolated from the ground beetle Pterostichus oblongopunctatus F. (Coleoptera, Carabidae) to study population structure. Each locus was polymorphic, with the number of alleles ranging from three to six. Observed heterozygosity varied between 0.20 and 0.67. All six loci were tested for amplification in the closely related P. quadrifoveolatus and they were shown to be polymorphic. The primers developed were used in multiplex polymerase chain reactions. [ABSTRACT FROM AUTHOR]