The genotype of an organism is determined primarily by its genetic makeup, which is inherited from its parents. This genetic composition is specifically defined by the alleles it carries for various genes, which can come in different forms. These alleles can be dominant or recessive and influence traits in combination with one another.
In organisms that reproduce sexually, half of the genetic material comes from the mother and half from the father. The combination of these alleles during fertilization establishes the genotype. Environmental factors can also play a role in how these genes are expressed, leading to variations in the phenotype, but the genotype itself is a fixed set of genes acquired at conception.
Understanding the genotype is crucial for fields like genetics, breeding, and medicine, as it provides insights into the inheritance of traits, potential genetic disorders, and the overall health of the organism.