Natural selection structured populations into highly interacting co-adapted gene complexes. Correlated multilocus units. Nonrandom patterns in electromorph frequencies. Inconstant rates of molecular evolution. When molecules first appear, often have very high rates of molecular evolution.
Evolution slows down once molecules near perfection.
Gametogenesis usually occurs in terminal modules, so strong selection occurs both within and between modules. However, unlikely to restrain selection at level of individual. Trait groups must disperse. Allele helps group members by enhancing productivity of group. Maintained in group when all demes come together.