Single Review on past events

When Claudius Kratochwil is being asked why he does the research he does he answers: “Because I believe that understanding nature better, helps me to convince more people to protect it”. In his project on the “Evolution of transcriptional regulation during diversification and speciation in cichlid fishes” he wants to find out how species are evolving and how the astonishing diversity we find in nature can be explained. His objects of interest are cichlid fishes, because with about 2.000-3.000 species they are one of the most diverse animal families.

In particular, he wants to find out how diversity in coloration of a cichlid species can be explained by changes in DNA. It can be explained by mutations, which are basically spelling errors of nature. “Mutations in the genome are like spelling errors in a text”, illustrated the biologist. “Some change the meaning completely, some make a minor difference, some don`t make a difference at all.” In the same manner not all mutations result in changes of how an organism looks like.”

But how to find out which ones do? Every cell has the same genes, but if they are on or off is controlled differently. Both, genes and regulatory elements mutate in the course of evolution and can change how an animal looks like. Mutations in genes can result in different proteins that can lead to a different phenotype. But also mutations outside of genes can cause changes - for example a missing fin - if they are regulatory elements that control if a gene is on or off in a certain tissue.

Claudius Kratochwil´s research questions go further: Can changes in gene regulation explain the extreme diversity in cichlid fishes? And how to find these elements in a systematic way? He pointed out: “Modifications in the proteins, which are bound to DNA regions, can tell you what these regions do.” By the sequencing of regions, which are enriched in these protein modifications, one can look through the whole genome of these animals, which parts are involved in the regulation of genes and if they are different or even missing in other cichlid fishes.

In order to validate that particular regulatory elements are really involved, he applies two possible methods: test the activity of regulatory elements, or test the function of genes and regulatory elements by deletion.

In the end he summarized the three parts of his project: screening for regulatory elements and comparative analysis, establishing methods to test gene and regulatory element function, as well as understanding the role of regulatory elements during the diversification of cichlids fishes.