FIGURE 2.

The DNA triangle. (A) Generalized model: thinking about DNA incorporates three different conceptual levels, all of which are linked: chromosomal, molecular, and informational. (B) DNA in the context of meiosis: understanding of the concept of ploidy relies on using information about DNA at the chromosomal and informational levels, the concept of homology relies on DNA knowledge at the informational and molecular levels, while the mechanism of homologous pairing relies on knowledge of DNA at the chromosomal and molecular levels.