= BAFsegmentation = BAFsegmentation is a method to identify regions of allelic imbalance from B allele frequencies obtained from SNP arrays described in ''Segmentation-based detection of allelic imbalance and loss-of-heterozygosity in cancer cells using whole genome SNP arrays'' [[BR]] J. Staaf, D. Lindgren, J. Vallon-Christersson, A. Isaksson, H. Göransson, G. Juliusson, R. Rosenquist, M. Höglund, Å. Borg, M. Ringnér [[BR]] ''Genome Biology'' '''9''':R136 (2008)[[BR]] [http://genomebiology.com/2008/9/9/R136/abstract Abstract] === License === The BAFsegmentation software is available as a stand-alone software package, and will become available as as a plug-in to BASE as the handling of SNP arrays in BASE is developed. Both versions are available under the [http://www.gnu.org/copyleft/gpl.html GNU General Public License]. === Download BAFsegmentation === The method will be downloadable as a stand-alone version soon. === How to use BAFsegmentation === ''Requirements'' BAFsegmentation is written in R with a Perl wrapper, so both R and Perl are required. Required Perl modules are: File::Spec, Getopt::Long, IO::File and Pod::Usage (http://www.cpan.org). Required R package is DNAcopy, recommended version is 1.14.0 (http://www.bioconductor.org). ''Installation'' Download and unzip the file available under the section ''Download BAFsegmentation'' on this page. OS X or Linux: The programs should run as they are. You need R and perl in your path. Windows: Depending on how you have installed R and Perl on your system you may have to edit the variables ''$R_command'' and ''$R_windows'' at the beginning of the file ''BAF_segment_samples.pl''. ''$R_windows'' should likely contain the full path to the R interpreter on your system. Also comment out (with an initial #) the ''$R_command'' used on OS X and Linux systems. For example, we have successfully used BAFsegmentation using !ActivePerl on a Windows system with the following ''$R_windows'': {{{ # Mac OS X and Linux # my $R_command="R --vanilla --no-save --slave < BAF_segment.R"; # Windows my $R_windows=File::Spec->canonpath('C:/"Program Files"/R/R-2.7.0/bin/Rscript'); my $R_command="$R_windows --vanilla BAF_segment.R"; }}} ''Input data format'' BAFsegmentation is applied to data exported from !BeadStudio. For a set of samples, the file exported from !BeadStudio should be tab-delimited in the following format: ||Name||Chr||Position||sample1.B Allele Freq||sample1.Log R Ratio||sample2.B Allele Freq||sample2.Log R Ratio||sample3.B Allele Freq||sample3.Log R Ratio||...|| ||rs12354060||1||10004||1||0.110391||1||-0.05188531||1||0.07706165||...|| ||rs2691310||1||46844||0.5519782||0.2984372||0.4636427||0.3640218||0.4393658||0.2589271...|| ||...||...||...||...||...||...||...||...||...||...|| The data extracted from !BeadStudio needs to be split into a separate file for each sample using the script ''split_beadstudio_samples.pl''. {{{ perl split_beadstudio_samples.pl --beadstudio_file=example/example_beadstudio_data.txt }}} where ''example_beadstudio_data.txt'' is a file exported from !BeadStudio in the format described above. This script will generate one file per sample together with a file ''sample_names.txt'' in the BAFsegmentation subdirectory ''extracted''. These files are used when BAFsegmentation is run and can be deleted once the samples are normalized. ''Performing BAFsegmentation'' In the BAFsegmentation directory, run BAFsegmentation with the following command: {{{ perl BAF_segment_samples.pl }}} This command will perform BAFsegmentation on the samples in the BAFsegmentation subdirectory ''extracted'' that are specified in the file ''sample_names.txt''. If you want to perform BAFsegmentation on a subset of samples you can edit ''sample_names.txt'' accordingly. The segmented data is stored in the BAFsegmentation subdirectory ''segmented''. === Supplemental Data === * The plots referred to in additional data file 4 in the manuscript are available [http://cbbp.thep.lu.se/~markus/publications/papers/BAFsegmentation_supplemental_data.zip here]. * The simulated data set used in the publication is available [http://cbbp.thep.lu.se/~markus/software/BAFsegmentation/SimulatedTumorData.zip here] * Infinium data for four matched tumor-normal pairs and a dilution series of a tumor cell line mixed with its paired normal cell line are available in NCBI's Gene Expression Omnibus with accession [http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE11976 GSE11976]. === Contact === If you have comments please send an email to johan.staaf@med.lu.se