EPISTACY: A SAS program for detecting two-locus epistatic interactions using genetic marker information


VERSION 2.0 IS AVAILABLE NOW!!! Links below are for updated version 2.0 files.

WARNING: IF YOU TRY TO RUN EPISTACY ON SAS VERSION 8, YOU MUST SUBMIT PROGRAM FROM THE REGULAR PROGRAM EDITOR - NOT THE ENHANCED PROGRAM EDITOR.

EPISTACY is a SAS program designed to test all possible two-locus combinations for epistatic (interaction) effects on a quantitative trait using QTL-mapping data sets.

The program is really a SAS program template that users must modify to suit their own data sets. In the simplest cases, users will need only to change the names of the files containing their data.  The program uses least squares methods and does not employ interval mapping methods.  The software is free to all.  If you use the software and find it useful, please send me an email to let me know.  Also, if you have problems or suggestions for improvement, let me know.  I will post updates here as they are developed.  You can reference the program for publication as Journal of Heredity 1998, Vol 89:374-375.


1 To start with, please read the UPDATED introduction and manual, available in PDF format.  You can download and print the manual on your own machine.

2 After reading the introduction, choose the program suitable for your type of population.  You can download to your own computer, save as a text file, and use that directly as the program file to run under the SAS system.  As described in the manual, you will need to modify the program to suit your data set by changing the data file names and the names of the marker loci to be tested.
 

3 Download example programs and data sets to see how the programs work:
 

4 If you are running the program under Windows 95, you need to "fix" your SAS program using the fiberfix software freely available from the SAS Institute.  Otherwise your SAS will crash after about twenty minutes of running the program.

5 Last remark: the number of tests performed by the program increases much faster than the number of markers used, so if you have a data set with a large number of markers, be prepared to let the program run a long time!