Difference Between Genotype and Phenotype

Introduction To Phenotype And Genotype Difference

Genotype can be described as the genetic makeup of an organism. As humans are diploid organisms, they have two alleles at each genetic position, with one allele inherited from each parent. Phenotype refers to the physical properties of an organism, which can be observed with our eyes. These include the organism's appearance, development, behavior, height, color of eyes, hairs, etc. The concept of genotype and phenotype was introduced by Johannsen in 1909, in his textbook on heredity research.

He further developed this concept in a paper named “The Genotype Conception of Heredity” in 1911. An organism's genotype affects its phenotype. Change in the environment also affects phenotype.

Comparison Chart Between Genotype and Phenotype

Basis for comparison 




The genotype is the hereditary information in the form of genes in the DNA which remains the same in an organism throughout its life.

Phenotypes are visible characters. These characters change from infant to adult.

Consist of

The organism's heredity characters that may or may not be expressed in the next generation.

In a particular environment, the same genotype produced the same phenotype.

Characters are not inherited hence it is said that same phenotypes may or may not belong to the same genotype.


The genotype is not visible

Phenotypes are visible 

Change with period

Does not change


It appears

As genetic material inside the body 

As physical appearance outside the body.


During reproduction, the genotype is partly inherited from an individual to the offspring as one of the two alleles.

These characters are not inherited 

Determined by

To find the kind of genes on the allele, scientific methods like polymerase chain are used.

By observation 

Factors Affecting Genotype And Phenotype

The genotype of a person can be affected by the environment in which the person lives and the internal environment of a person's body such as hormones and metabolism. Phenotype is affected by the genotype of a person.

Genotype In Biology

Genotype helps to determine the heredity potentials and limitations of an individual from the embryonic stage through adulthood. Among sexually reproducing organisms, a genotype contains the entire complex of genes inherited from both parents.

Examples of Genotype

Example 1

In the pea plant, the possible genotypes for the flower- color gene was red - red, red- white, and white- white.

Example 2

Considering the genotype for height in a species of a pea plant, T is for tall variety and s small variety. T and s can be known as alleles as they are the variations in the same character, called “height of a pea plant”. If T is dominant, four possible combinations will be Ts, ss, TT, sT. It is considered that pure breed of plants is TT and ss, then the probability of offspring being short is 1 in 4.

Phenotype In Biology

Physical characters of an individual that are observable, is the phenotype of that individual.

Examples of Phenotype

  • Sound of your voice 

  • Length of a fox’s tail

  • Colour of stripes on the cat

  • An individual's shoes size

  • Size and shape of the spots on the dog's back

Types of Genotype

A combination of alleles situated on corresponding chromosomes determines a person's specific traits. The genes responsible for traits such color of the skin can be the example of a genotype.

There are three types of genotypes. They can be distinguished based on alleles of a person.

  • Homozygous dominant, PP

  • Heterozygous, Pp

  • Homozygous recessive pp

The ability to survive intensive breeding depends on adjusting the system of a genotype to different conditions. Different species have different genotype adaptability, hence there is a constant natural selection.

The Strongest Genotype

The genotype having more dominant genes are considered as strongest. Dark hair, Right handedness, Brown eyes, Broad eyebrows, Left thumb crossing, Long eyelashes, Left arm over right, Broad lips, etc.  In hot climate regions, certain races have broad lips as their dominant gene.

FAQ (Frequently Asked Questions)

1. It is necessary to have Genotype compatibility for marriage? Why?

People who are incompatible based on their genotype, have a big risk of giving birth to an immature child. A child can be born with serious diseases such as sickle cell disease. It reduces the lifespan of a child. This is the reason why before getting serious with a partner, one should have to pass a genotype test. There was a high mortality rate in the past among children who were born to parents with incompatible genotype. A few genotypes determine one's traits and the traits of future children. They are AA, AS,  AC, and SS  These are hemoglobin Genes. Genotype AC is uncommon, together with genotype SS, it is considered abnormal. In genetics, it is referred to as sickle cells.   AA and AS are normal genotypes.

2. How is blood type inherited?

Blood type in humans is inherited similarly to many other traits. Punnett squares are used to determine the genotype and phenotype of offspring. There is not a single inheritance pattern that governs all blood types. Recessive blood type is always “O”. It requires two copies of the O alleles for an offspring to demonstrate the O phenotype. A and B are blood types and both are dominant. So, as a result, there can be blood type A or B by inheriting two copies of A or B allele and one copy of the allele O