Neuro-cognitive models of word learning propose a role for sleep in consolidating new words, yet evidence for sleep-associated memory benefits outside of experimental contexts is scarce. This study compared wake- and sleep-associated memory changes in data from Memrise, a publicly available language-learning app. Memory for foreign words and phrases remained very high in accuracy across a 7-12 hour delay, and there were no differences in forgetting between wake and sleep. However, learners were quicker to arrive at the correct translation after a period of sleep compared to wake. This sleep-associated benefit was seen for words but not phrases, and could not be fully accounted for by circadian differences in completion time. As such, we demonstrate that the behavioural benefits of sleep on vocabulary can be observed in real-world language learning, and discuss the promise for combining small- scale lab studies with naturally occurring datasets to understand learning outcomes.

Although high-throughput RNA sequencing (RNA-seq) has greatly advanced small non-coding RNA (sncRNA) discovery, the currently widely used complementary DNA library construction protocol generates biased sequencing results. This is partially due to RNA modifications that interfere with adapter ligation and reverse transcription processes, which prevent the detection of sncRNAs bearing these modifications. Here, we present PANDORA-seq (panoramic RNA display by overcoming RNA modification aborted sequencing), employing a combinatorial enzymatic treatment to remove key RNA modifications that block adapter ligation and reverse transcription. PANDORA-seq identified abundant modified sncRNAs-mostly transfer RNA-derived small RNAs (tsRNAs) and ribosomal RNA-derived small RNAs (rsRNAs)-that were previously undetected, exhibiting tissue-specific expression across mouse brain, liver, spleen and sperm, as well as cell-specific expression across embryonic stem cells (ESCs) and HeLa cells. Using PANDORA-seq, we revealed unprecedented landscapes of microRNA, tsRNA and rsRNA dynamics during the generation of induced pluripotent stem cells. Importantly, tsRNAs and rsRNAs that are downregulated during somatic cell reprogramming impact cellular translation in ESCs, suggesting a role in lineage differentiation.