chrom
 chr11:69464719-69502928
 chr7:55075808-55093954
 chr8:128739772-128762863
 chr3:169389459-169490555
 chr17:37848534-37877201
 chr19:30306758-30316875
 chr1:150496857-150678056
 chr12:69183279-69260755
 chr11:77610143-77641464
 chr8:38191804-38260814
 chr12:58135797-58156509

chr       chrStart           chrEnd
chr11     69464719         69502928
chr7      55075808         55093954
chr8      128739772        128762863
chr3      169389459        169490555

PeakBoundaries$chrOnly <- PeakBoundaries[grep("\w+?=\:"),PeakBoundaries$chrom]