The range expression, for example:
join(61..70,121..130) or
join(complement(61..70),complement(121..130))
The sequence with index, for example:
61 ttcttctatt cattgcatag atcttctact
91 gttgctgttg ctgttgaggt acaatacagt
121 ctgacagaag gaactatttt agtccttcta