Genotype vs Phenotype- What’s the Difference?

Genotype is the inherited (from parents) genetic instructions, while phenotype is the observable result expressed from those instructions. The main difference between genotype and phenotype is the difference of instruction vs. expression.

The genotype represents the underlying genetic instructions. In comparison, the phenotype is the observable expression of these instructions, expressed as the organism’s physical and functional characteristics.

Key Differences

• Focus: Genotype focuses on the internal, coded instructions, while phenotype focuses on the external, observable expression.
• Deterministic vs. Probabilistic: Genotype sets the potential, but phenotype is shaped by gene-environment interactions, making it less predictable.
• Inheritance vs. Influence: Genotype is directly inherited, while both genes and environment influence phenotype.

Genotype vs Phenotype

Here are the main differences between Genotype and Phenotype:

Factors	Genotype	Phenotype
Definition	Genetic makeup of an organism	Observable physical traits or characteristics of an organism
Composition	Combination of alleles inherited from parents	Expression of genes and interaction with the environment
Representation	Represented by letters or symbols	Represented by physical appearance or traits
Influence	Determines the potential traits an organism can have	Determines the actual traits expressed by an organism
Inheritance	Passed down from parents to offspring	May be influenced by both genetic and environmental factors
Variability	Can vary within a population	Can vary among individuals within a population
Examples	AA, Aa, bb, CC	Brown hair, blue eyes, tall stature

Difference Between Genotype And Phenotype Example

Example: Hair color

Genotype: This refers to the specific combination of alleles you inherit for the hair color gene, represented by letters like AA (both brown hair alleles), Aa (one brown and one blonde allele), or aa (both blonde hair alleles).

Phenotype: This is your actual hair color, which results from the expression of your genotype. While someone with an AA genotype will most likely have brown hair, the environment (e.g., nutrition) and other genes can influence the exact shade or even cause exceptions.

Conversely, someone with Aa genotype could have brown or blonde hair depending on the expression of their alleles.