When two DNA nucleotide sequences are aligned and a gap is observed in one of the sequences, why do we collectively refer to insertions and deletions as “indels”?

Answer 1

We collectively refer to insertions and deletions as “indels” because they both result in an alteration in the length of the DNA sequence. An insertion adds one or more nucleotides to the sequence, while a deletion removes one or more nucleotides. Both types of alterations can create gaps in the alignment of the two sequences, which is why the term “indel” is used to describe them together.