In Drosophila, the wing disc‐associated muscle precursor cells give rise to the fibrillar indirect flight muscles (IFM) and the tubular direct flight muscles (DFM). To understand early transcriptional events underlying this muscle diversification, we performed single‐cell RNA‐sequencing experiments and built a cell atlas of myoblasts associated with third instar larval wing disc. Our analysis identified distinct transcriptional signatures for IFM and DFM myoblasts that underlie the molecular basis of their divergence. The atlas further revealed various states of differentiation of myoblasts, thus illustrating previously unappreciated spatial and temporal heterogeneity among them. We identified and validated novel markers for both IFM and DFM myoblasts at various states of differentiation by immunofluorescence and genetic cell‐tracing experiments. Finally, we performed a systematic genetic screen using a panel of markers from the reference cell atlas as an entry point and found a novel gene, Amalgam which is functionally important in muscle development. Our work provides a framework for leveraging scRNA‐seq for gene discovery and details a strategy that can be applied to other scRNA‐seq datasets.

中文翻译：

---

成年肌肉前体的细胞图谱揭示了果蝇纤维类型差异的早期事件。

在果蝇中，与机翼盘相关的肌肉前体细胞产生原纤维间接飞行肌肉（IFM）和肾小管直接飞行肌肉（DFM）。为了了解这种肌肉多样化背后的早期转录事件，我们进行了单细胞RNA测序实验，并建立了与第三龄幼虫翼盘相关的成肌细胞细胞图集。我们的分析确定了IFM和DFM成肌细胞的独特转录特征，这些特征是其差异的分子基础。该图集进一步揭示了成肌细胞分化的各种状态，从而说明了它们之间先前未曾意识到的时空异质性。通过免疫荧光和遗传细胞示踪实验，我们鉴定并验证了处于不同分化状态的IFM和DFM成肌细胞的新标记。最后，汞合金在肌肉发育中起重要作用。我们的工作提供了利用scRNA-seq进行基因发现的框架，并详细介绍了可应用于其他scRNA-seq数据集的策略。