Dear all,

Question 1: If I have a set of specimens which are object symmetry, how 
could I calculate directional asymmetry *(DA) score* for this set of 
specimen? I noted that after using bilat.symm function in geomorph, 
DA.component could be extracted, which contains two sets of coordinates. I 
guess DA score of the sample could be calculated from DA.component, can 
anyone show me the code necessary to derive DA score, whether in geomorph 
or any other software?

Question 2: A possibly related question is how (appreciated if R code is 
provided) to obtain the *Procrustes distance between two specimens after 
GPA*. I think I can calculate the Procrustes distance between the original 
and reflected and relabled mirrors for each specimen and averaging the 
Procrustes distance across all specimens to obtain DA score for my entire 

Question3: A third question which is unrelated to the previous two is that 
I noted that Procrustes Variance is used in Morphol.disparity function to 
compare morphological disparity across groups. Procrustes Variance is 
explained in the user manual as "the sum of the diagonal elements of the 
group covariance matrix." But where can I find some more *detailed 
mathematical definition of Procrustes Variance*?

Thank you very much for your help!

Best regards,
Patrick Wen

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