Here is an example of volcano plot produced using edgeR results on DEG analysis. So my question is why there is no values in the middle of plot (indicated by red circle)?

![Volcano plot][1]


  [1]: https://i.pinimg.com/originals/07/69/3d/07693dfcb3c8fe55fcae39d7caa64239.jpg
You are plotting the fold change of differential expression versus the confidence in detecting this differential expression. (q-value)  Genes which have a low fold change will generally have a higher q-score.