My goal is to create a 3-dimensional graph with an X,Y, and Z axis (with 2 X axis, actually).
My problem is that I have large data sets, and a large portion of my Y data and Z data are generated via VLOOKUP, and MOST of the cells return n/a with only about 1% having real data in them that I'm interested in.

For the Y axis this is not a problem because it just ignores the cells with n/a and only plots the cells with values. Great.
However, the Z axis isn't a true Z axis, but rather Categories relating to X,Y. Right? The Z axis isn't Z at all, but is in fact "Names". Therefore it wants to list every N/A and data, generating thousands of categories in a key to the right hand side of the graph.

My question: Is there a simple way that I can add a Z axis that behaves as the X and Y axis do? Note, I am NOT asking about adding another Y axis, because that would NOT makes sense at all. If you are having a hard time understanding for what application this might be necessary I will explain below:

My specific data are values from 3 sources: 1) The X-axis will be position along a genome. A genome (for our purposes) is a list of letters A, G, T, and C (these letters make up your DNA). The particular one I'm interested in is 9,800 letters long. 2) The Y-axis is the frequency (%) that a mutation occurs at a site (so if the third letter in the genome happens to be a G, but 12% of the time it's an A instead, the Y value would be 12 at that spot on the X axis). 3) The Z-axis should be time. This will be an odd number from 1 to 27, which represents the time-point that the sample was taken from (sadly enough, primates are infected and blood samples are taken every other week).

So in conclusion, a data point would represent 1 mutation ocurring X% of the time at 1 spot on the genome at a certain time point.

Is excel capable of handling this?