Are the apparent populations defined in advance or only suggested by the patterns you see after looking at the data? If predefined then there are methods. If they are only suggested by the data then real testing is difficult. Because the differences are only along PC1 one wonders whether these may just be size classes corresponding to age classes - or do they correspond to different geographic regions?
------------------------ F. James Rohlf, Distinguished Professor Ecology & Evolution, Stony Brook University www: http://life.bio.sunysb.edu/ee/rohlf > -----Original Message----- > From: morphmet [mailto:[EMAIL PROTECTED] > Sent: Thursday, November 08, 2007 7:17 AM > To: morphmet > Subject: PCA clusters > > Dear morphometricians, > > I have the following problem: > > I have performed a PCA of shape (relative warps analysis) on a set of > mouse mandibles from animals of different geographic origins. Now in a > plot of PC1 vs PC2, I can "see" that PC1 sorts specimens into broadly > overlapping clusters corresponding to the respective origins of the > mice, while PC2 (and the other PCs) do not. The problem is now that the > overlaps of the "population" clusters are rather broad so the question > is how different they actually are. Also, I have several "populations", > so it looks like a continuum of overlapping clouds. > Could you recommend a means to quantify and/or somehow test the actual > differences between "populations" along PC1? > > Louis Boell > > ----------------------------------------------------------------------- > - > Machen Sie Ihre E-Mail-Kontakte zu Messenger-Freunden! Einfacher > Adressimport! > <http://redirect.gimas.net/?cat=hmtl&n=M1007AI&d=http://messenger.live. > de/ersteschritte_adressimport.html> > > -- > Replies will be sent to the list. > For more information visit http://www.morphometrics.org -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
