title: How to overlay a Seaborn jointplot with a "marginal" (distribution histogram) from a different dataset
body: <p>I have plotted a Seaborn <code>JointPlot</code> from a set of &quot;observed counts vs concentration&quot; which are stored in a pandas <code>DataFrame</code>. I would like to overlay (on the same set of axes) a marginal (ie: univariate distribution) of the &quot;expected counts&quot; for each concentration on top of the existing marginal, so that the difference can be easily compared.</p>
  <p>This graph is very similar to what I want, although it will have different axes and only two datasets:
  <img src="https://i.stack.imgur.com/W8jHf.png" alt="" /></p>
  <p>Here is an example of how my data is laid out and related:</p>
  <p><strong>df_observed</strong></p>
  <pre><code>x axis--&gt; log2(concentration): 1,1,1,2,3,3,3 (zero-counts have been omitted)
  
  y axis--&gt; log2(count): 4.5, 5.7, 5.0, 9.3, 16.0, 16.5, 15.4 (zero-counts have been omitted)
  </code></pre>
  <p><strong>df_expected</strong></p>
  <pre><code>x axis--&gt; log2(concentration): 1,1,1,2,2,2,3,3,3
  </code></pre>
  <p>an overlaying of the distribution of <code>df_expected</code> on top of that of <code>df_observed</code> would therefore indicate where there were counts missing at each concentration.</p>
  <p><strong>What I currently have</strong></p>
  <p><img src="https://i.stack.imgur.com/9leCC.png" alt="Jointplot with the observed counts at each concentration" />
  <img src="https://i.stack.imgur.com/L11Iw.png" alt="Separate jointplot of the expected counts at each concentration. I want the marginal from this plot to be overlaid on top of the marginal from the above jointplot" /></p>
  <p>PS: I am new to Stack Overflow so any suggestions about how to better ask questions will be met with gratitude. Also, I have searched extensively for an answer to my question but to no avail. In addition, a Plotly solution would be equally helpful. Thank you</p>