Introduction: The key characteristics of positron emission tomography (PET) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. Therefore, accurate quantification is important. However, it can be sensitive to several physical factors. The aim of this investigation is the assessment of the e...

With the genomic sequencing of Arabidopsis nearing completion and rice sequencing very much in its infancy, a key question is whether we can exploit the Arabidopsis sequence to identify candidate genes for traits in cereal crops using a map-based approach. This requires the existence of colinearity between the Arabidopsis and cereal genomes, represented by rice, which is readily detectable usin...

In bacterial genomes, gene order is not random. This is most evident when looking at operons, these often encoding enzymes involved in the same metabolic pathway or proteins from the same complex. Is gene order within operons nonrandom, however, and if so why? We examine this issue using metabolic operons as a case study. Using the metabolic network of Escherichia coli, we define the temporal o...

The identification of homologous regions between chromosomes forms the basis for studies of genome organization, comparative genomics, and evolutionary genomics. Identification of these regions can be based on either synteny or colinearity, but there are few methods to test statistically for significant evidence of homology. In the present study, we improve a preexisting method that used coline...

Denis Duboule is one of the most influential and highly-cited scientists in developmental biology. Born in Geneva in 1955, he holds dual Swiss and French nationality. His undergraduate studies in biology at the University of Geneva included research on mouse embryology. He later learned molecular techniques in the laboratory of Pierre Chambon, becoming a major player in characterising the newly...

Grasses are the single most important plant family in agriculture. In the past years, comparative genetic mapping has revealed conserved gene order (colinearity) among many grass species. Recently, the first studies at gene level have demonstrated that microcolinearity of genes is less conserved: small scale rearrangements and deletions complicate the microcolinearity between closely related sp...

Vertebrate Hox genes are activated in a spatiotemporal sequence that reflects their clustered organization. While this colinear relationship is a property of most metazoans with an anterior to posterior polarity, the underlying molecular mechanisms are unknown. Previous work suggested that Hox genes were made progressively available for transcription in the course of gastrulation, implying the ...