Welcome, Guest. Please Login
YaBB - Yet another Bulletin Board
 
  HomeHelpSearchLogin  
 
BranchSiteREL with small number of taxa (Read 2896 times)
antben
YaBB Newbies
*
Offline


Curious HyPhy user

Posts: 2
BranchSiteREL with small number of taxa
Apr 1st, 2014 at 4:28pm
 
Hi all,

I have sequence data for a total of eight taxa and would like to test for positive (or, failing that, relaxed) selection in three of these taxa, none of which are each other's closest relatives. From what I have gathered, eight taxa is not enough to get dependable results from a BranchSiteREL test and, in these situations, the GA-Branch test may be better. However, this latter test seems like it has been pretty aggressively phased out in favor of BranchSiteREL. Is it reasonable to use BranchSiteREL with eight taxa and, if not, can you suggest a more appropriate test? Is the GA-Branch test still implemented?

Thanks,
Ben
Back to top
 
 
IP Logged
 
Sergei
YaBB Administrator
*****
Offline


Datamonkeys are forever...

Posts: 1658
UCSD
Gender: male
Re: BranchSiteREL with small number of taxa
Reply #1 - Apr 1st, 2014 at 4:47pm
 
Hi Ben,

The number of taxa are not what determines the power of BranchSiteREL -- sequence divergence and sequence length do. You are probably thinking of MEME (which IS powered by the number of taxa). You should be able to use BranchSiteREL without any issues. If you use the standalone version of BranchSiteREL in HyPhy you can also restrict the set of branches to test to only the three you had selected a priori. This will reduce the number of tests done and boost the power as well (less stringent multiple testing correction).

Sergei

PS We are also developing a test for relaxation of selection, based on the same formalism as BranchSiteREL, but using a different set of models. This test has not been published yet, but if you are interested e-mail Joel Wertheim in my group for details.
Back to top
 

Associate Professor
Division of Infectious Diseases
Division of Biomedical Informatics
School of Medicine
University of California San Diego
WWW WWW  
IP Logged
 
antben
YaBB Newbies
*
Offline


Curious HyPhy user

Posts: 2
Re: BranchSiteREL with small number of taxa
Reply #2 - Apr 2nd, 2014 at 12:41pm
 
Hi Sergei,

Yes, I must have misread something. Thank you very much for your response. I definitely will contact Joel Wertheim to ask about the test for relaxed selection.

Thanks again,
Ben
Back to top
 
 
IP Logged