>chr1
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
>chr2
aaaaaCTGAaaaaaaaCTGAaaaaa
>chr3
CTGAaaaaaaaCTGA
>chr4
CTGACTGA
>chr5
TCAGaaaaaaTCAG
>chr6
tcagAAAAAAtcag
>chr7
AATGATG
CATGATG
TATGATG
GATGATG
AGTGATG
CGTGATG
TGTGATG
GGTGATG
>chr8_no_valid_C_boxes
ACTGATG
CCTGATG
TCTGATG
GCTGATG
ATTGATG
CTTGATG
TTTGATG
GTTGATG
>chr9
CATCACCCATCACACATCACGCATCACTCATCATCCATCATACATCATGCATCATT
>chr10
AATGATG
aaaaaaa
CTGAaaa
ccccccc
AATGATG
aaaaaaa
CTGAaaa
ccccccc
AATGATG
aaaaaaa
CTGAaaa
