Path: utzoo!utgpu!watserv1!watmath!uunet!mailrus!iuvax!bionet!niu.bitnet!T80SMS1
From: T80SMS1@niu.bitnet
Newsgroups: bionet.population-bio
Subject: Phylogenetic correlations
Message-ID: <9005281409.AA22851@genbank.bio.net>
Date: 28 May 90 02:01:00 GMT
Sender: daemon@genbank.BIO.NET
Lines: 22

>I've been trying to figure out the Cheverud-Dow-Leutenegger (CDL) method of
>phylogenetic autocorrelation, and am stuck.
>The equations implied by this path diagram are
>
>         r = s1 s2 rS + q1 q2 rP
>         1 = s12 + q12
>         1 = s22 + q22
>
>where r is the correlation between X1 and X2.  CDL's autocorrelation method
>gives us the values of s1 and s2, and the 2nd and 3rd equations then tell us
>q1 and q2.  This leaves 1 equation in two unknowns (rS and rP), which would
>appear to have no unique solution.  Can anyone suggest where we might find
>n additional equation that might give this system a sensible answer?

My understanding is that rP is determined from independent
information, ie. other characters are first used to determine
the phylogeny.  Thus, equation 1 has only 1 unknown and a
unique solution.

Sam Scheiner
Northern Illinois University
t80sms1@niu.bitnet