Research

The IEB lab studies coloration, an important and fascinating organismal feature. Coloration plays key roles in fundamental physiological, ecological, and evolutionary processes. We study coloration phenotypes to gain an integrative understanding of how genetic, developmental, and cellular changes lead to evolutionary diversification.

The research of our lab is currently focusing on two lines of research:

  • The genomic bases of coloration phenotypes and their evolution
  • The cellular and tissue dynamics underlying the development and differences in coloration

 

Cichlid fishes are an excellent model system for understanding phenotypic diversification from a genomic standpoint. They are a famous example of explosive adaptive radiation — in less than a few million years over 1,200 species evolved in the three East African Lakes Victoria, Tanganyika, and Malawi. This astonishing rate of diversification makes them a suitable family of vertebrates to investigate the genetic changes associated with the diversification of traits, including coloration.

Coloration is undoubtedly one of the traits that strongly affected the adaptation and exceptional rate of speciation. The exceptional degree of phenotypic diversification we find in cichlids is only associated with a very low degree of genetic diversification. As a result of recent divergence, many cichlids can be hybridized permitting Quantitative Loci Mapping (QTL) studies. Also, we established a state-of-the-art toolset including Crispr-Cas9 mutagenesis and Tol2-transgenesis that allow us to confirm and further investigate target genes and mutations. We take advantage of this exceptional model system to study fascinating genotype-phenotype relationships.

Relevant publications:

 

The color of tissues results from the multi-layered organization of pigment cell types with different structural and pigmentary properties. On a macroscopic scale, the emergence of particular color patterns arises from spatial differences in pigment cell properties and arrangements.

To understand how color patterns are formed by the concerted action of pigment cells in the skin, we use state-of-the-methodologies to analyze cellular differences (single-cell RNA-sequencing) and the three-dimensional arrangement of pigment skills (fluorescence microscopy and 3-dimensional electron microscopy).

Cichlids are also ideal for monitoring the development of pigmentation phenotypes, which constitutes a further approach that we take advantage of. The development and formation of pigmentation phenotype can be followed over days and weeks and development — an analysis that is particularly powerful when different species that vary in their adult patterns are investigated.

Relevant publications