text: user3171: I was confused about the VlnPlot that it shows like the screenshot. It only shows the dot but no distribution of the data, is that normal?
  
  user3541: I assume you are referring to VlnPlot() of Seurat. The reason that you are getting such a plot is because your distribution is highly skewed, most of your points are zeros, not surprising for scRNA-seq. And the plot is actually showing your distributions, it is just the points at zero stacking on top of each other.
  You can double check this by plotting a histogram for each of the clusters.
  An example violin plot:
  
  Cluster 0, which is mostly zeros, kind of looks like yours.
  
  Cluster 6, which I believe is what you would expect to see, contains a lot of cells that express the gene and much less skewed, hence the shape denoting the density.
  
  So what you are seeing is normal, your gene is not expressed/not detected is all.
  
original_text: 3171: <p>I was confused about the VlnPlot that it shows like the screenshot. It only shows the dot but no distribution of the data, is that normal?<a href="https://i.stack.imgur.com/CYjGQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CYjGQ.png" alt="enter image description here"></a></p>
   3541: <p>I assume you are referring to <code>VlnPlot()</code> of Seurat. The reason that you are getting such a plot is because your distribution is highly skewed, most of your points are zeros, not surprising for scRNA-seq. And the plot is actually showing your distributions, it is just the points at zero stacking on top of each other.</p>
  
  <p>You can double check this by plotting a histogram for each of the clusters.</p>
  
  <p>An example violin plot:</p>
  
  <p><a href="https://i.stack.imgur.com/BMK1r.png" rel="noreferrer"><img src="https://i.stack.imgur.com/BMK1r.png" alt="enter image description here"></a></p>
  
  <p>Cluster 0, which is mostly zeros, kind of looks like yours.</p>
  
  <p><a href="https://i.stack.imgur.com/0oMTG.png" rel="noreferrer"><img src="https://i.stack.imgur.com/0oMTG.png" alt="enter image description here"></a></p>
  
  <p>Cluster 6, which I believe is what you would expect to see, contains a lot of cells that express the gene and much less skewed, hence the shape denoting the density.</p>
  
  <p><a href="https://i.stack.imgur.com/kBC32.png" rel="noreferrer"><img src="https://i.stack.imgur.com/kBC32.png" alt="enter image description here"></a></p>
  
  <p>So what you are seeing is normal, your gene is not expressed/not detected is all.</p>
  