Question

what is the original DNA sequence

Answer 1

I am not sure I understand exactly what you mean.  DNA contains a "code" for producing the things the cell needs. The code is different in all organisms.  Think of the DNA as the library of information inside of the cell. The entire library is in every cell but not all cells use the whole library. When the cell wants to use part of the DNA it must be copied or transcribed. Those instructions can then be used to create a protein which functions within the cell to do a job.  RNA is a temporary copy of part of the DNA. Almost like taking a photocopy from the library. The book remains in the library unchanged but the copy can be taken outside of the library and used in many different ways.  Hope this helps.  Ask more questions if you need more help.

Answer 2

You're going to need to be more specific.

If, for example, one sequence was ATTGCCGATT, then the other sequence would be TAACGGCTAA. Just remember that A always goes with T (and vice-versa), and G always goes with C (and vice-versa).