A complex organism uses the DNA to its full potential. For example, some genes are regulated by a large number of enhancers, which results a combinatorial compl

A complex organism uses the DNA to its full potential. For example, some genes are regulated by a large number of enhancers, which results a combinatorial complexity. That is, you don't need a large number of regulators for your system. Instead, there's just a handful, but they're mixed and matched to create thousands of combinations. Alternative splicing and post-translational modifications contribute to complexity as well, as you can create hundreds of thousands of protein variants with relatively few genes. And not to forget that genome is highly dynamic: there're constant rearrangements, which allow producing complex patterns of gene expression.