To zoom in / zoom out a dotplot you can:

<center>
     <br>
     <img src="/wiki/download/attachments/4227420/Navigating in Dotplot.png"/>
     <br>
</center>

To move the zoomed region you can:

<center>
     <br>
     <img src="/wiki/download/attachments/4227420/Navigating in Dotplot_1.png"/>
     <br>
</center>
<center>
     <br>
     <img src="/wiki/download/attachments/4227420/Navigating in Dotplot_2.png"/>
     <br>
</center>