What is the difference between a genotype and a phenotype?
The genotype is the set of genes in our DNA which is responsible for a particular trait. The phenotype is the physical expression, or characteristics, of that trait. For example, two organisms that have even the minutest difference in their genes are said to have different genotypes.
The genome in which a genotype is found can affect the expression of that genotype, and the environment can affect the phenotype. Genes can also be pleitropic when they affect more than one trait. The single base pair mutation that lead to sickle cell anemia is a classic example.
- Phenotype and genotype. The genotype of an organism is defined as the sum of all its genes. The phenotype of an organism is the observable physical or biochemical characteristics of an organism, determined by both genetic make-up and environmental influences.
- The degree to which your phenotype is determined by your genotype is referred to as 'phenotypic plasticity'. If environmental factors have a strong influence, the phenotypic plasticity is high. If genotype can be used to reliably predict phenotype, the phenotypic plasticity is low.
- A phenotypic trait is an obvious, observable, and measurable trait; it is the expression of genes in an observable way. An example of a phenotypic trait is hair color. Underlying genes, which make up the genotype, determine the hair color, but the hair color observed is the phenotype.
An excellent example of multiple allele inheritance is human blood type. Blood type exists as four possible phenotypes: A, B, AB, & O. There are 3 alleles for the gene that determines blood type. (Remember: You have just 2 of the 3 in your genotype --- 1 from mom & 1 from dad).
- In other words, Mendel was unaware of the phenomenon of INCOMPLETE DOMINANCE. With incomplete dominance, a cross between organisms with two different phenotypes produces offspring with a third phenotype that is a blending of the parental traits. It's like mixing paints, red + white will make pink.
- Phenotypic ratio pertains to the relative number of offspring manifesting a particular trait or combination of traits. It can be determined by doing a test cross and identifying the frequency of a trait or trait combinations that will be expressed based on the genotypes of the offspring.
- Reginald Punnett and William Bateson were among the first English geneticists. Punnett devised the "Punnett Square" to depict the number and variety of genetic combinations, and had a role in shaping the Hardy-Weinberg law. Punnett and Bateson co-discovered "coupling" or gene linkage.
The physical appearance of an organism as distinguished from its genetic makeup. The phenotype of an organism depends on which genes are dominant and on the interaction between genes and environment. Compare genotype.
- Genotype versus phenotype. An organism's genotype is the set of genes that it carries. An organism's phenotype is all of its observable characteristics — which are influenced both by its genotype and by the environment. For example, differences in the genotypes can produce different phenotypes.
- Recessive and dominant alleles. You will recall that genes have different forms called alleles. An allele can be recessive or dominant. A recessive allele only shows if the individual has two copies of the recessive allele.
- Phenotype is the observable physical or biochemical characteristics of an individual organism, determined by both genetic make-up and environmental influences, for example, height, weight and skin colour.
Updated: 21st September 2018