Wikipedia is a great _reference_ but not necessarily the best way to learn about a topic. Of course, this depends on the topic, on who has been writing the page, etc

A particularly bad example is higher maths - a wiki pages on a complex mathematics topic often reads like "A gruncheon is a worch in the brashation of plusters" and each of these words is a separate page or topic. Of course, you _can_ in theory 'just' click through all the tree of linked pages to understand a concept ...

For DNA the page (scanning it now) is well laid out, with images (including a spinning Rasmol? image) and lots of detail. However, the detail could be a drag on understanding for some : There are 'nucleotides' and 'nucleosides' and 'nucleobases'? There are non-canonical bases? Supercoiling? Z-DNA? While I know (most) of these things, it is because I've learned about them in other contexts, or by direct instruction.

I'm not saying it is impossible to understand DNA from that page, but it is likely to be harder (for some?) than a more conversational approach to learning.