al= (int)( (dra.low+side + al)/2 )+1;
}
if((drb.high-side) < bh){
bh= (int)( (drb.high-side + bh)/2 );
}
DirectionalGenomicRegion drll= new DirectionalGenomicRegion(dra.chr, dra.strand, al, a),
drlh= new DirectionalGenomicRegion(dra.chr, dra.strand, a+1, ah),
drrl = new DirectionalGenomicRegion(drb.chr, drb.strand, bl, b),
drrh = new DirectionalGenomicRegion(drb.chr, drb.strand, b+1, bh);
if(dra.isOnForwardStrand()){
gbtup.add(drll);
gbtdown.add(drlh);
}else{