Mid-Term Report Summary - HAPSELA (Haploid selection in animals: investigating the importance of genetic and epigenetic effects in sperm)
In our quest to identify genetic and epigenetic effects under selection during the haploid phase of a the life cycle of an animal, the zebrafish, we managed to provide unequivocal evidence for a strong role of selection on sperm phenotype in offspring fitness. The results were obtained from a large scale selection experiment over three generations, which we are currently coupling with whole-genome sequencing and RNAseq of sperm pools as well as offspring from several generations to shed light on the underlying mechanisms. As part of this process, we also developed a protocol to perform single-cell genotyping on individual zebrafish sperm, which we will employ to improve our understanding of the link between sperm phenotype and genotype. Furthermore, we identified differences in the RNA profile of zebrafish males exposed to different environmental conditions, which we are now linking to potential differences in chromatin structure and methylation in the sperm of such males. The results obtained so far support the importance of selection during the gametic phase for evolutionary processes.