This is one of those areas where the apparently-not-so-tyrannical-after-all Church does not bind the conscience of the individual. Consequently, you will get many varied interpretations of the Genesis account. You will get 7-day literalist to evolutionists, with the whole spectrum in between also represented.
BUT! Those who affirm evolutionary theory cannot deny some form of original sin. I happen to fall into this category. I believe that the Genesis account conveys truth in the form of a popular folk-tale (some people call it “myth”, as a form of literature, not the all-too-common popular definition of “false”), the type that would have been told around fires underneath the stars for generations. Thus, the truth conveyed seeks to answer the questions, who, what, and why, and not to answer the question of how. Specifically, Genesis reveals that a good God created the universe out of nothing, that human beings are the crown of his creation, created good and to be in relationship with him, that humans fell, reaped the consequences of that fall, and that God promised to somehow redeem humanity.
What the “evolutionary Catholic” would deny is that God created the world in 7 literal days. In other words, he would affirm that God created the world through the process of evolution. God is still the creator. It’s just that evolutionists would posit a different means of creating than would the 7-day literalists.