The entire genome is selected for, not individual genes

Human Genome

The entire genome is selected for in nature, not the indvidual genes, which under natural selection are chosen or discarded based on their phenotypic characteristics.

This means that the genotype, whatever it may be, is not selected for, but its expression as a phenotype is the characteristics which either nature, or in sexual selection, the female will choose a mate based on her preferences of his behavior and traits. Reproductive success, then is partially a matter of appreciating phenotypic display and the chances of retaining desired phenotypes in sexual selection and less debilitating phenotypes in natural selection.