What controls the development from a fertilized egg to a multicellular organism?

During the development from a single cell progenitor to a fully grown organism with up to hundreds of tissue types, the basic gene repertoire remains almost constant, however, the activity of genes (gene expression levels) differ tremendously across cell and tissue types. Developmental biology tries to understand the underlying differentiation processes which turn genes on and off in a tightly controlled spatio-temporal manner and thus makes each individual of a species as recognizable specimen of its kind.
Gene expression levels can be regulated at many different levels. During my PhD I analyzed the binding of specialized proteins, so called transcription factors to DNA and their impact on gene expression. Despite enormous technological advances during the last couple of years, to really understand the highly dynamic nature of gene regulation, high-resolution temporal data of various molecular processes at a cellular level are required, which is technically still quite challenging. For my PostDoc, I therefore decided to focus on a more stable system, which is the change of DNA sequences over time, also known as genome evolution.

What generates diversity across species?

The genome is defined as the entirety of an organism's hereditary information. Almost all of our cells harbor the complete DNA sequence information to generate a fully grown organism and mutations in the DNA may lead to changes in morphology. Morphological diversity that is seen throughout the animal kingdom is a product of mutational events that occurred in single individuals and got fixated through a series of more or less random processes, such as drift, selection, or demographic events. Although it is impossible to go back in time and to actually observe the evolutionary events that lead to the existing diversity, comparisons of sequences that are separated by different time spans, may reveal basic insights into what kind of events dominate at a population or at a cross-species level and how variable evolutionary forces are over time.

Why studying nematodes?

Nematodes constitute a highly attractive model for studying all aspects of animal biology including evolution. One very exceptional aspect of nematodes is that their development resembles an almost completely deterministic process that results in a fixed number of cells in the mature animal (at least in Caenorhabditis elegans ). They are therefore assumed to be one of the least complex animal systems to study. At the same time, the possibility to keep them easily under laboratory conditions and their short generation times makes them a great model for genetic experiments that try to link phenotypic traits to the underlying genes. In addition, their small genome size allows sequencing and analysis of reasonable numbers of strains and species. My current position in the sommerlab at the MPI for developmental biology gives me the opportunity to work independently on existing genomic data or to generate new data sets but also to interact with other people and to figure out what all the A,C,G, and T letters are actually doing.