FastaSequenceExtractor se= new FastaSequenceExtractor(gen, gbout);
SequenceExtractorEntry en;
while( (en= se.nextEntry())!=null ){
GenomicRegion gr= en.getGenomicRegion();
NucleotideSequence seq= NucleotideSequenceParser.parseSequence(en.getSequence());
double at= seq.atContent();
bw.write( gr.toBedFormat()+"\t"+ ((double)Math.round(at*100)/100)+"\n" );
}
bw.close();
}