Genotype

The genotype is the specific genetic makeup of an individual, in the form of DNA. Together with the environmental variation that influences the individual, it codes for the phenotype of that individual. Non-hereditary mutations are not classically understood as representing the individuals’ genotype. Hence, scientists and doctors sometimes talk for example about the type of a particular cancer, thus separating the disease from the diseased. While codons for different amino acids may change in a random mutation, this doesn't necessarily alter the phenotype.

Typically, one refers to an individual's genotype with regard to a particular gene of interest and, in polyploid individuals; it refers to what combination of alleles the individual carries. Any given gene will usually cause an observable change in an organism, known as the phenotype. The distinction between genotype and phenotype is commonly experienced when studying family patterns for certain hereditary diseases or conditions, for example, hemophilia. Sometimes people who do not have hemophilia can have children with the disease, because the parents each "carried" hemophilia genes in their body, even though these genes have no effect on the parent’s health.