So what is a PCA?

[Stefan]

For a while now I've wondered what the eigenvectors and eigenvalues mean in the context of the PCA plots we use to structure genetic results (I knew of eigenvectors/values in other contexts: Linear Algebra & Physics.) Interestingly, it has to do with the statistics involved, and it is quite a clever idea actually. I found a blog that explains it very simply. For those who are interested, check it out.

http://georgemdallas.wordpress.com/2013/10/30/principal-component-analysis-4-dummies-eigenvectors-eigenvalues-and-dimension-reduction/