Abstract

Cytosine DNA methylation is one of the most widespread epigenetic marks in eukaryotes. Its roles encompass various gene regulatory processes, including imprinting, X-chromosome inactivation and transposable element silencing. However, our knowledge on DNA methylation mainly derives from vertebrate model systems, which have an inherent bias: vertebrate genomes are hypermethylated (>70% of CpGs are methylated), which is the exception rather than the rule in the animal kingdom. In my work, I challenge many of the assumptions in the field of DNA methylation taking a comparative epigenomic approach, using non-traditional animal and protistan species to decipher how various aspects of this epigenetic layer have evolved. In this talk I will discuss our latest results describing the origins of the DNA methylation system in animals and its impact on vertebrate brain evolution. This work provides a provocative insight on how changes on epigenetic information might have influenced organismal complexity and genome organisation in the animal kingdom.