Blank Spaces In Conservation Tracks

Question

[anuragm]

I came across many regions in the conservation tracks that do not have data for conservation values. My guess they might be regions that are not present across all the taxa considered or just regions that could not be amplified. Still could anyone tell me the other possibilities for 'missing data' in these regions ?

[Giovanni M Dall'Olio]

They are probably gaps in the alignment or huge deletions. Anyway, can you please provide an example of these "missing regions", just for clarity?

[Neilfws]

Assuming from the tag "ucsc" that these are UCSC genome browser tracks; that could be clearer in your question.