Additive phenotypic effects, fitness landscapes, and X-linkage.

<p>Expression level of a gene (dashed blue line) and relative fitness (solid green curve) are plotted for genotypes at a locus with two alleles ( and ). The alleles have additive phenotypic effects, with each copy of increasing expression level. (A) The locus is autosomal with phenotypic and fitness measurements collected in females or males, or it is X-linked with measurements collected in females. (B) The locus is X-linked and not dosage compensated with measurements collected in males.