Figures & data
Figure 1. Outline of the mechanisms acting on the gene organization of a region of extended collinearity conservation across Diptera species. The region shown is a composite of constraints of several types (top solid lines, 1–5) acting on independent or on overlapping domains. Domain 2 encompasses two genes whose expression is mediated by regulatory sequences (green ovals) acting at long distance or coordinating the expression of several genes (dotted arrowhead lines). Between those particular regulatory sequences and their target genes other structurally and functionally unrelated genes might exist (bystander genes). Domain 1 and 5 correspond to chromosome stretches that encompass yet-to-be annotated genes or functional features (orange arrows), which are assumed to be relevant for organismal fitness. Domains 3 and 4 (blue boxes) correspond to chromosomal stretches that are exposed to molecular environments associated with reduced probabilities of chromosomal breakage in the germline. Red arrowheads denote chromosomal breakpoints that demarcate the boundaries of the region conserved across species. The left boundary corresponds to a fragile region susceptible to chromosomal breakage due to particular sequence features. The right boundary corresponds to the physical limit of two overlapping constraints. Black arrows, protein- and non-coding genes.
