Clarinet Plots: Alternative to Violin Plots to Display Zero-inflated Distribution of scRNA-seq Data

Generally, scRNA-seq data contain many 0 values, and the expression of each gene shows a zero-inflated distribution. Therefore, violin plots are usually used to display distributions of scRNA-seq data because they can represent the shape of multi-modal distributions. However, when the proportion of 0 values is very large, the 0 peak becomes too large in a violin plot, and the shape of the distribution of non-zero values becomes difficult to see. To resolve this issue, in this study, clarinet plots are proposed as alternative to violin plots to display zero-inflated distribution of scRNA-seq data. In clarinet plots, each distribution is represented by a clarinet-like shape. The long axis corresponds to quantile, and the width represents the magnitude of each data value. The straight line at the end corresponds to 0 values. By using a clarinet plot, the proportion of 0 values and the distribution of nonzero values can be displayed simultaneously and effectively. Examples of application to artificial data and real data are shown.