for (i in 12:15){
 print (colnames(x)[i])
 tt=summary(x[,i]>1)
 print(tt)
 }
+ + + + [1] "KO_0h_replicate_I.bam"
   Mode   FALSE    TRUE    NA's 
logical    3110   15498       0 
[1] "KO_0h_replicate_II.bam"
   Mode   FALSE    TRUE    NA's 
logical    3160   15448       0 
[1] "WT_0h_replicate_I.bam"
   Mode   FALSE    TRUE    NA's 
logical    2145   16463       0 
[1] "WT_0h_replicate_II.bam"
   Mode   FALSE    TRUE    NA's 
logical    3079   15529       0 
> for (i in 8:11){
 print (colnames(x)[i])
 tt=summary(x[,i]>0)
 print(tt)
 }

+ + + + [1] "KO_0h_replicate_I.bam"
   Mode   FALSE    TRUE    NA's 
logical     681   17927       0 
[1] "KO_0h_replicate_II.bam"
   Mode   FALSE    TRUE    NA's 
logical     566   18042       0 
[1] "WT_0h_replicate_I.bam"
   Mode   FALSE    TRUE    NA's 
logical     392   18216       0 
[1] "WT_0h_replicate_II.bam"
   Mode   FALSE    TRUE    NA's 
logical    1541   17067       0