Quantifying the genetic origins of body plan scaling

Many of the higher organisms have remarkably consistent body proportions where, within a given species, the sizes of the different body parts, such as the head or the legs, scale with the size of the organism. To probe the origins of body plan scaling, one should study early stages of development where this property is established. Drosophila melanogaster is arguably the most suited organism for such a study since decades of research have enabled measurements of the relevant developmental markers with unprecedented precision. Specifically, we now have access to the expression profiles of all developmental genes that jointly orchestrate the body plan formation of the fruit fly through a complex network of interactions. The richness and quality of measurement data in the fly embryo call for a comparable level of quantitative rigor in studying the question of spatial scaling—a challenge that Nikolić et al. embark on in their recent PNAS publication (1).