Continuous listbox row text select

I’m looking for some advice on selecting part or the whole text in a listbox row. That spans multiple rows, by skipping rows.

I’m writing an application that views and edits DNA. I’ve created a code that imports each line as a row to a list box. And it works well. I’ve also added code to create a new row for compliment DNA stand and a row for Amino Acids.

Row 1 = DNA
Row 2 = Compliment
Row 3 = Amino Acids