Other projects

Besides the current projects in my lab, I have previously worked on the following topics. I am deeply interested to pick up the threads sometime to continue on these issues.

Cyprinid hybrids are so abundant, that if one catches a fair number of the parental species some hybrids can usually be found as long as one has a trained eye to identify them.

Cyprinid hybrids are so abundant, that if one catches a fair number of the parental species some hybrids can usually be found as long as one has a trained eye to identify them.

Genetics of isolation in Cyprinid fishes

European Cyprinids have long been known to hybridize frequently across species and genus boundaries and more than 50 different interspecific hybrids have been described. Some of these hybrids have been shown to be fertile and to occur at high frequencies sometimes outnumbering their parents in nature. We are intrigued by the apparent success of Cyprinid hybrids and want to assess their fitness and whether they mediate gene flow between long separated genera of fishes. To this end we are developing a SNP panel to study genetic isolation on a genome wide scale and we have generated an EST library for studies of gene expression from massively parallel sequencing data. Together with the group of Prof. Dr. Petr Rab (Institute of Animal Physiology and Genetics, Czech Republic) and Dr. Jörg Freyhof (IGB, Berlin, Germany) we are interested to integrate results from genomic and cytogenetic approaches with ecological studies to understand the evolutionary role of cyprinid hybrids.

Genetic sequence analysis (left) confirms what can be seen from phenotypes (right). A hybrid (middle) shows intermediate traits that originate from its parental species (top and bottom) (Pictures: A. Hartl).

Genetic sequence analysis (left) confirms what can be seen from phenotypes (right). A hybrid (middle) shows intermediate traits that originate from its parental species (top and bottom) (Pictures: A. Hartl).

Reticulate evolution in the Telmatherina species flock in the Malili Lakes

I have participated in research conducted by Dr. Fabian Herder (ZFMK, Bonn, Germany) and Dr. Ulrich Schliewen (ZSM, Munich, Germany) that aimed to understand the evolution of sailfin silversides in the Malili Lakes in central Sulawesi, Indonesia. This species flock is interesting because it contains convincing examples for sympatric speciation. Moreover, we detected abundant signs for reticulate evolution within closed lake systems, which points towards a possible role that hybridization may have played in the evolution of sailfin silversides. We plan to assess the prevalence of natural hybrids in the lake system and to study whether genomic islands of divergence have emerged among the parental species during 1-2 my years of evolution to further understand the evolutionary impact of hybridization.

Sailfin Silversides have undergone an adaptive radiation in the Malili – Lakes in central Sulawesi. The fact that the base of some branches of this network based on molecular markers are reticulate and broad suggests that hybridization has played a role in the evolution of the present diversity.

Sailfin Silversides have undergone an adaptive radiation in the Malili – Lakes in central Sulawesi. The fact that the base of some branches of this network based on molecular markers are reticulate and broad suggests that hybridization has played a role in the evolution of the present diversity.

Transcriptome divergence in young species pairs of whitefish

Whitefishes of the genus Coregonus offer a unique opportunity to study the evolutionary genetics of speciation. Multiple lakes in eastern Canada and North-eastern United States contain sympatric pairs of Dwarf and Normal whitefish that have evolved in parallel. I have received a postdoctoral research stipend to join the Laboratory of Prof. Dr. Louis Bernatchez at Université Laval in Quebec, Canada. The work Dr. Sébastien Renaut and I did was designed to analyse the nature of postzygotic isolation in young species pairs of whitefishes (Coregonus spec.) in order to learn how reproductive barriers evolve. Gene expression profiling was used to screen for traits in which hybrids differ from their parents and to study the ontogeny of a complex adaptive phenotype at the transcriptome level.