The key difference between genotype and blood group is that a genotype is an organism’s complete set of genetic material or an individual’s collection of genes, while blood group refers to the entire blood group system comprising red blood cell (RBC) antigens whose specificity is controlled by a series of genes.
Genotype is one of the factors that determine the physical appearance or the phenotype of a person. There are different genes for different traits. Genotype is often described as the version of DNA sequences an individual possesses. Blood groups deal with the red blood cells. In fact, blood groups are categorised based on the antigens (proteins) on the cell surface of the red blood cells.
CONTENTS
1. Overview and Key Difference
2. What is a Genotype
3. What is a Blood Group
4. Similarities Between Genotype and Blood Group
5. Side by Side Comparison – Genotype vs Blood Group in Tabular Form
6. Summary
What is a Genotype?
A genotype is the complete set of genetic material in an organism. The term genotype was coined by the Danish botanist Wilhelm Johannsen in 1903. Genes control the characters (phenotype) that are observable in an individual – for example, hair colour, eye colour, height, etc. Genotype often refers to a single gene or set of genes, such as the genotype for eye colour. The collection of all genetic possibilities for a single trait, such as petal colour in a pea plant, is known as alleles. In this example, the two alleles for petal colour are purple and white. The phenotype of an individual is controlled by three factors. Genotype is one factor. The other two factors are environment (not inherited) and epigenetic (inherited).
Figure 01: Genotype
Individuals with the same genotype do not look the same because appearance and behaviour are modified by the environment and growing conditions. In the same way, all organisms that look alike do not necessarily have the same genotype. An individual’s genotype would be typically described as homozygous or heterozygous with regard to a particular gene of interest and the combination of alleles the individual carries. When the identical alleles of the gene are present, it is called homozygous. When the gene carries two different alleles, it is called heterozygous.
What is Blood Group?
Blood group is the classification of blood, based on inherited differences (polymorphisms or variations) in antigens found on the surfaces of red blood cells. Red blood cells have certain proteins called antigens on the surface. The plasma contains antibodies that will attack certain antigens if they are present. Both ABO and rhesus are antigens present on the red blood cell surface. Therefore, an individual can either have blood group A, B, AB or O based on the above antigens present on the red blood cell surface. The ABO blood type was the first blood type to be discovered.
Figure 02: Blood Group
Most people are rhesus positive if they have rhesus antigens on their red blood cell surface. However, 3 in 20 people do not have rhesus antigen on their red blood cell surface and are said to be rhesus negative.
What are the Similarities Between Genotype and Blood Group?
- Genotype and blood group are determined by inherited genes.
- They both have genes with alleles.
What is the Difference Between Genotype and Blood Group?
Genotype is an organism’s complete set of genetic material or an individual’s collection of genes. In contrast, blood group refers to the entire blood group system comprising red blood cell (RBC) antigens whose specificity is controlled by a series of genes that can be allelic or linked very closely on the same chromosome. Thus, this is the key difference between genotype and blood group. In simple words, the genotype is present inside every cell, while the blood group is determined by the antigens found outside a red blood cell.
The below infographics lists the differences between genotype and blood group in tabular form.
Summary – Genotype vs Blood Group
Genotype is one of the factors that determine the physical appearance (characters) or phenotype of an individual. It is usually transferred from parents to the offspring. Blood groups just deal with just red blood cells. A blood group is controlled by proteins (antigens) situated on the surface of a red blood cell. The genotype is inside every cell. On the other hand, the blood group is outside a red blood cell. Thus, this is the difference between genotype and blood Group.
Reference:
1. “Genotype.” Wikipedia, Wikimedia Foundation, 11 Jan. 2021, Available here.
2. “Blood Groups.” NHS Choices, NHS, Available here.
Image Courtesy:
1. “SimpleGenotypePhenotypeMap” By Alphillips6 – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “1913 ABO Blood Groups” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
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