Summary How epigenetic information is transmitted from generation to generation remains largely unknown. Deletion of the C. elegans Histone H3 lysine 4 dimethyl (H3K4me2) demethylase spr-5 leads to inherited accumulation of the euchromatic H3K4me2 mark and progressive decline in fertility. Here we identified multiple chromatin-modifying factors, including novel H3K4me1/me2 and H3K9me3 methyltransferases, an H3K9me3 demethylase and an H3K9me reader, which either suppress or accelerate the progressive transgenerational phenotypes of spr-5 mutant worms. Our findings uncover a network of chromatin regulators that control the trans-generational flow of epigenetic information, and suggest that the balance between euchromatic H3K4 and heterochromatic H3K9 methylation regulates trans-generational effects on fertility.

The vast amount of available spatio-temporal data of human activities and mobility has given raise to the rapidly emerging field of urban computing/informatics. Central to the latter is understanding the dynamics of the activities that take place in an urban area (e.g., a city). This can significantly enhance functionalities such as resource and service allocation within a city. Existing literature has paid a lot of attention on spatial dynamics, with the temporal ones often being neglected and left out. However, this can lead to nonnegligible implications. For instance, while two areas can appear to exhibit similar activity when the latter is aggregated in time, they can be significantly different when introducing the temporal dimension. Furthermore, even when considering a specific area X alone, the transitions of the activity that takes place within X are important themselves. Using data from the most prevalent location-based social network (LBSN for short), Foursquare, we analyze the temporal dynamics of activities in New York City and San Francisco. Our results clearly show that considering the temporal dimension provides us with a different and more detailed description of urban dynamics. We envision this study to lead to more careful and detailed consideration of the temporal dynamics when analyzing urban activities.

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