How are genotypes used to determine phenotypes?

Each gene has its own rules of interaction between the alleles; some have dominance relationships, some have codominance relationships; some genes interact with other genes, and the number of genes they interact with varies from gene to gene. Therefore, the phenotype depends on the alleles available, the type of relationship between them, and whether or not there is an interaction with other genes. Per gene, there may be two or more alleles available in the gene pool of the species.

Genotypes determine phenotypes through the expression of genes. Genotypes represent the genetic makeup of an organism, including the alleles inherited from both parents. Phenotypes, on the other hand, are the observable traits or characteristics of an organism, influenced by its genotype and environmental factors. The interaction between alleles and the expression of genes determines how traits manifest in an individual, leading to specific phenotypic outcomes.