Any organism is made up of the interaction between genes and the environment. The genetic makeup of any organism is the genotype, whereas the physical attribute shown by the organism’s gene is the phenotype.
Genotype and phenotype, although related, have huge differences. Genotype is the genetic material passed down from generation to generation. But phenotype is the observable characteristic of the genetic material. Traits of organisms is another name for a phenotype. Understanding the genotype vs. phenotype is essential for any biologists, especially those involved in the study of genetics. The concept of genotype and phenotype was given by Wilhelm Johannsen in 1911 while proposing “The Genotype Conception of Heredity.”
Image source: Genotype
Genotype
A gene is a section of DNA (deoxyribonucleic acid) that encodes any particular trait in any organism. The accuracy in the arrangement of nucleotides in a gene differs between the copies of the same gene. So, the gene is present across different organisms. The various forms are called alleles. The exact position of the gene in the DNA (chromosome) is the locus.
Diploid organisms like humans obtain have two alleles at each locus. Each allele is inherited from the two parents. The pair of alleles represent the genotype. So, the genotype can be termed the formation of genes in any organism.
A genotype can be homozygous or heterzygous. Homozygous genotypes have two identical alleles, whereas heterozygous genotypes have two different alleles. The alleles of the organisms expressing similar traits can be dominant or recessive. Dominant alleles are expressed over the recessive alleles.
Examples of genotype
- The eye color of humans:
For this example, let us consider the eye color can be brown or blue. The brown eye color is the dominant trait and the letter “B” represents the allele. The blue eye is the recessive trait, letter “b” denotes the allele. The alleles for the eye color of the person are inherited from each of the parents. The alleles for brown eye color can be either BB (homozygous) or Bb (heterozygous). And the alleles for the blue color will be bb, the only genotype that can express the eye color blue.
Image source: Eye color
- The color of the flower of the sweet pea:
Likewise, let us take the purple and white colors of the sweet pea flower. The purple color is the dominant gene, and the letter “F” represents its allele. The white color is the recessive trait, and the letter “f” represents the allele. The purple color trait occurs if the plant has an “FF” or “Ff” genotype, but only an “ff” genotype gives the white color trait.
- The hair color of humans:
Similarly, among the many hair colors of humans, let us consider brown and blond hair colors. The brown hair color is dominant here, and the letter “B” represents the allele. Whereas the letter “b” represents the allele for blond hair (recessive trait). The possible genotypes are “BB,” “Bb,” and “bb.” The BB and Bb will give brown hair color, and the bb genotype gives blond hair color.
- The hair texture of humans:
The hair texture of humans can either be curly or straight. Curly hair is the dominant trait, and the “C” represents the allele, whereas straight hair is the recessive trait, “c” defines the allele. People with curly hair have the genotypes “CC” and “Cc.” The genotype “cc” gives straight hair.
Phenotype
The phenotype is the sum of an organism’s appearance, development, and behavior or simply observable physical characteristics. The genotype of the organism determines the phenotype of the organism. The environment and mutations also influence the phenotype of the organisms. So, the organism’s phenotype depends on environmental factors, mutation, and genotype.
Examples of phenotype
- Human skin color:
The melanin content in the human’s skin color may depend on the allele obtained from the parents. But it keeps changing over a period of time due to exposure to sunlight and various other factors.
- The skin color of the flamingo:
The well known color of flamingo is vibrant color pink, which is not its actual color. Its inherited color is white, which changes to pink due to its diet.
- Identical twin children having different features:
The genotype of the identical twin children is almost similar, but due to exposure to different environmental factors, they exhibit different behavioral patterns and slightly different appearances.
- Wing length of fruit fly:
The wing length of the fruit fly is dominantly longer, but due to various environmental and genetic factors, the wing length shortens over time.
- The height of humans:
Although genotype can play role in the height of humans, the offspring of parents with taller height can be short and vice versa. This is because of physical exercise, diets, and other environmental factors.
Genotype Vs. Phenotype
As discussed above, the phenotype’s determinant is related to the genotype. Although related, the genotype and phenotype have many differences in their definition, factors affecting them, the process of acquiring them, etc.
Definition
The genotype is the set of genes present as alleles in the DNA of any organism that gives rise to a particular trait. In contrast, the phenotype is the sum of all the organism’s observable characteristics obtain due to genotype or environmental factors.
Acquired by
The genotype is acquired due to inheritance. In contrast, the phenotype may be inherited or developed due to prolonged exposure to different environmental factors.
Affecting factors
The parental genes affect the genotype of the organisms, but the environmental factors and parental genes affect or bring change in the phenotype.
Observed by
The genotype remains within the DNA, so it is hard to observe. So, genotyping methods like PCR (polymerase chain reaction) and whole genome sequencing help observe the genotype.
The phenotype is the observable traits of organisms and does not require any such methods for
Example
The allele B represents the brown eye color, and the allele b represents the blue eye color in humans. Therefore, the genotype BB and Bb leads to the person having brown eye color, and bb gives the blue eye color.
Humans’ skin color may be brown, black, or Caucasian (white) due to the concentration of melanin. The melanin concentration depends on the genotype, but the UV rays of the sunlight also affect it. So, skin tone and color change in people with prolonged exposure to sunlight.
Summary Chart of Genotype Vs Phenotype
| Properties | Genotype | Phenotype |
| Definition | The genetic makeup of any organism that determines its features of the organisms. | The observable characteristics of any organism are termed phenotype. |
| Acquired by | It is acquired by inheritance (from parents to offspring). | It is either inherited or acquired after exposure to environmental factors. |
| Observed by | Whole genome sequencing, PCR, DNA microarray, DNA hybridization, etc., help to observe the genotype. | Since phenotype is the observable character, no extensive tests are required for observing it. |
| Affecting Factors | The genetics of the parents affect the genotype. | The genotype and environmental factors affect the phenotype. |
| Examples | Examples of genotypes are; the eye color of humans expressed by the alleles BB, Bb, and bb, etc. | Examples of phenotypes are; the concentration of melanin in the human skin, the color of flamingo, etc. |
References and further reading
- genotype | Learn Science at Scitable. Nature.com. Retrieved 22 August 2022, from https://www.nature.com/scitable/definition/genotype-234/.
- Phenotype. Retrieved 22 August 2022, from https://www.genome.gov/genetics-glossary/Phenotype
- phenotype / phenotypes | Learn Science at Scitable. Nature.com. Retrieved 22 August 2022, from https://www.nature.com/scitable/definition/phenotype-phenotypes-35/.
