Well without teleological understandings we are left only with efficient causality which, as Hume said loose and separate and therefore we are left with Humean puzzles of causality or as Aquinas put it if a cause does not follow an end of final cause then there is no reason why one effect should follow orderly and regularly from a cause, except by chance. But even beyond that talk of DNA is suffused with terms like information, encoding, blueprint and such. This is much more in line with a teleological approach than a non-teleological one and indeed with the regularity and intentionality of DNA a naturalistic explanation is not just improbable, and question-begging anyway, but really illogical.
You didn't answer the question. DNA is intentional in the philosophical sense;
Intentionality (Stanford Encyclopedia of Philosophy)
It is impossible to talk of DNA except in terms of information or the like, as in in terms of intention and purpose. DNA is
of some other state. You stop talking about it in this way and you become incoherent.