Finding structure within a string

Question

thank you for looking at my first post. I need to find within a string of substantial length, patterns that will allow me to break that string up into components of structure. This question is related to a biological sequence where in DNA there are regions that code for genes, and regions that do not. The only characters permitted are A,C,G,T. Assume that the regions that are coding and non-coding are unknown. Thus the goal is the find a pattern within the string that allows differentiation of coding and non-coding regions. In reality, there are known coding regions but I wanted to figure out how to approach this problem in the absence of this information. I have a few ideas but I wanted to see how you experienced programmers and mathematicians would approach this. I am a beginner programmer and I do not have a background in maths thus I am hoping to learn from you all. Thank you for your attention.