At fertilization, the male and female pronuclei undergo a transformation from germline to pluripotency as they fuse, marking the beginning of Drosophila embryogenesis. As the vital parental load of RNAs into the embryo is decreasing, the zygote takes control of its genome in a process called the maternal to zygotic transition. Several small non-coding RNAs (sRNAs) have regulatory roles during this transition, including e.g. microRNAs and piwi-interacting RNAs (piRNAs). Here, we want to investigate the dynamics of the piRNA population in early-stage Drosophila embryos by comparing the expression from single embryos of the first five developmental stages. In addition, we also want to study the paternal sRNA load and its impact on the embryo, with focus on sRNA modifications, as well as gene- and transposon expression using complete or partial deletion of the paternal microRNA 309 cluster. For this purpose, we want to analyze sRNA- as well as total RNAseq data from early-stage single embryos of wild type and embryos from microRNA 309 depleted fathers. We will also include CUT&RUN data of early Drosophila embryos to track sRNA expression in relation to histone modifications.