Update README.md

README.md

@@ -97,7 +97,7 @@ Lollipop map is an efficient method to display gene mutation sites and frequenci
 ![Lollipop map of mutation](https://github.com/ZhijianZhou01/BioAider/blob/master/Figures/Lollipop%20map.png)
 In BioAider, you only need to prepare the corresponding matrix file and simply set the parameters to quickly complete the drawing.
 
-### 4.3 Figure of sequence alignment
+### 4.3. Figure of sequence alignment
 Since version 1.727, BioAider has added a sequence editor, which supports sequence viewing and editing. More importantly, you can export the sequence alignment diagram very easy, and BioAider supports custom colors for each base (or amino acid).
 ![alignment_diagram](https://github.com/ZhijianZhou01/BioAider/blob/master/Figures/alignment%20_seqs.png)