Evolution and development (what Darwin would have loved to know)

We are working in a field at the interface of Evolution and Development. Our key question is: What changes in gene function and gene regulation accompanied the evolution of different morphological forms?

Innumerous and diverse species have developed in the course of life history. According to the ideas of Darwin, the evolution of new species is driven by variation and subsequent selection of those individuals that are best adapted to the environment. Darwin's central idea - that evolution creates species diversity - is not debated among scientists. But there is ongoing debate about what mechanisms are most important for speciation and what variations were actually necessary for the evolution of new body forms. Darwin could only speculate about how organisms inherit traits and how this heredity can possibly vary. Now we know that heredity is linked to the DNA of an organism and that a highly complex interplay between many genes is necessary to develop a complex body starting from a fecundated egg. Evo-devo scientists seek to find out what genes actually changed in what way in order to create novel body forms.

Evolution of early development

In Drosophila, early development is largely understood. One way answering evo-devo questions is therefore to isolate homologs of these genes in other organisms (for instance Tribolium) and compare their function. To this end, we use zygotic and parental RNAi (gene knock-down in the offspring of injected females). The latter is especially useful for analyzing the expression of genes in knockdown embryos.

However, the homolog gene approach cannot uncover genes that are important in Tribolium but not Drosophila development. Therefore, independent approaches are required to isolate such genes. Recently, a toolkit of widely applicable transposons and markers has been developed that allows for transgenic approaches in Tribolium. Using this toolkit, we are performing an insertional mutagenesis screen to uncover genes involved in segmentation, leg and head development.

© Gregor Bucher, last update: december 07