Genome evolution in fish - a story of DNA methylation, gene duplication and pregnancy


Jan Engelhardt

Unit for Theoretical Biology, Department of Evolutionary Biology
University of Vienna


DNA methylation is a crucial, abundant mechanism of gene regulation in vertebrates. In many invertebrate organisms it is less prevalent and the loss of individual DNA methyltransferases (DNMTs) independently occurred multiple times across ecdysozoan phyla. While DNMTs are frequently lost in invertebrates, in vertebrates occasionally new copies of DNMTs arise. Most commonly this happens after whole genome duplications (WGD). We have studied the gain of DNMT enzymes after the Teleost-specific 3R WGD as well as the salmonid and carp-specific 4R WGD. The latter one, beeing one of the most recent WGD in vertebrates. The retention of different classes of DNMTs gives interesting insights into the possible subfunctunalization of genes after a WGD event. Using zebrafish as model organism we study these subfunctionalizations experimentally, as well, using knockout experiments.

Finally, I will present the first steps of a new project started at the University of Vienna in which we generate a new genome of a viviparous fish. It belongs to the Goodeidae Allotoca goslinei. A very rare Cyprinodontiformes with less than 200 living specimen left.