Error in seq.default in chromPlot
Using this data frame:

gaps
  Chrom Start      End    Name
1     I     0 15072434 contigs
2    II     0 15279421 contigs
3   III     0 13783801 contigs
4    IV     0 17493829 contigs
5     V     0 20924180 contigs
6     X     0 17718942 contigs
7 MtDNA     0    13794 contigs


and this command:

chromPlot(bands = gaps)


I could obtain this plot:



and then, if you want to add some segments for a subset of bases, you can do:

gaps2 &lt;- gaps[1:2, ]
gaps2$End[2] &lt;- 7000000

chromPlot(bands = gaps, segment = gaps2)


and obtain the following plot:



A more satisfactory answer could put segments of different colour on the chromosome, so bands but this is the best I've got so far.