A quick visit to CPAN and a search on DNA gave 6 pages of modules where people have coded stuff to work with DNA base sequences and similar.

I've not looked deeply as although my degree is in Biochemistry I never really enjoyed genetics that much.

Why not have a quick snoop over there and see if someone already has solved this problem?

Not saying that there won't be those who sniff at the danger and love the challenge to develop new ways to do it better, that's partly what perl is all about.

Update It seems some folk don't like this post. I guess that's what lifes about here in the monastery.

It's just that I have noticed a fair few questions that appear to be about DNA bases and initially was going to suggest collecting some of the best responces and putting in a module. There are already plenty of DNA modules though hence the suggestion to check CPAN.

The code solutions provided illustrate the latter point that TMTOWTDI is alive and well.