-------- Original Message --------
Subject: Modularity in the human skull
Date: Sun, 3 Apr 2011 07:06:05 -0400
From: Hans Wellens <[email protected]>
To: <[email protected]>
Dear All,
To investigate modularity in the modern human skull, I`ve collected a
sample of some 200 subjects (mixed male and female, no specific age
restrictions). The idea is to calculate the multi-set RV coefficient
(Klingenberg) for three different scenarios often hypothesized to exist
by orthodontists and maxillofacial surgeons. MorphoJ would be used for
this purpose. I first wanted to make sure that male and female subject
could effectively be pooled. The idea was to determine whether they
differed in shape (differences in size are to be expected) and whether
the underlying covariance structures were similar. The Procrustes ANOVA,
which is based on the covariance matrix of a pooled generalized
Procrustes superimposition, indicates a highly significant difference in
shape. When superimposing the male and female mean configurations, the
differences are however incredibly small (hardly visible). I can of
course run the modularity tests separately for both sexes, but that
renders basically the same results as running the test on the pooled
sample. Nevertheless they seem to vary slightly differently. On the
other hand, it would seem logical to assume the same, or at least highly
similar interactions, be it anatomic, genetic, or functional, should
occur between the modules of male and female patients. So my common
sense tells me to go ahead and pool the sample, notwithstanding the
result of the Procrustes ANOVA. What do you think?
Hans Wellens, DDS
Orthodontist
Groene-Poortdreef 16
8200 Sint-Michiels, Brugge
[email protected]
