RASA 2.4 -negative tRASA

[Jenny Xiang]

> Dear All,

> I use RASA to examine phylogenetic signals in a data matrix and to detect
> potential long branches. The analysis gave me a negative value of tRASA (the
> observed slope is smaller than the null slope). I wonder how I should
> interpret this result.
>  Does it mean that the pairwise synapomorphies decrease as the pairwise
> similarities increase?  If tRASA
> is - 16.60314 for df = 1221, should this tRASA be significant since the
> absolute value of this tRASA is greater than the critical value (1.96 for df
> > 120 at p = 0.05)?

> I tried to contact Dr. Lyons-Weiler, the author of RASA, but my email was
> undeliverable to the address provided in the manual.  Help from any of your
> will be very much appreciated!

Sincerely,
Jenny

--
Jenny Qiu-Yun Xiang
Assistant Professor
Department of Biological Sciences
Idaho State University
Pocatello, ID 83209-8007
Phone: 208-282-4062
Fax: 208-282-4570
e-mail: xianjenn at isu.edu
http://www.isu.edu/~xianjenn/