Clearly, both "nature" and "nurture" are involved in developing intelligence (of which IQ is only one measure).

My parents were post-war immigrants who had only basic educations. Therefore, our home was not exactly a hotbed of intellectual stimulation.

But they must have had some decent genes and plenty of common sense, because my siblings and I did quite well in school, learned to function in society quite well, and continued to educate ourselves well after we graduated.

The way I see it, nurture seems to have a greater effect than nature. (Although I will readily admit that that is not always the case.)

Sure, our genes and our DNA are the blocks from which we are built, but our true essence is in the heart of the structure built by those blocks. In our hearts and in our minds. Which can grow and develop only if properly nurtured.