It is an essential requirement for people to care about their health, but ironically not many can define what a genotype is. Simply defined, a genotype is the entirety of the genetic constitution of a human being. It encompasses the genetic makeup of either a single or group of organisms concerning a single trait, set of attributes, or even a totality complex of characters. In simple terms, it is a person’s complete heritable genetic identity transmitted from parents through genes. There are many types of genotype, and they all have something to do with a person's blood group.
A genotype is something all individuals should know and even take into consideration when choosing a life partner. This is because there may arise compatibility issues which may lead to devastating effects during and after conception. Since you do not want to conceive children with sickle cell anemia and other health complications, you should check blood group compatibility with your partner before making the big decision to bring children into this world.
How genotypes come about
What is genotype? To understand what it is first, you have to know all about genes and chromosomes. Genes are found in chromosomes. Chromosomes are tightly-packed DNA structures found in the cell nucleus. They come in pairs in organisms that reproduce sexually.
One chromosome comes from the male, while the other comes from the female. Similarly, there are two copies of genes present in a chromosome, one from each parent. Different versions of a gene are called alleles, and when alleles are inherited from parents, they form what is known as a genotype.
Types of genotype and their characteristics
A person's specific traits are determined by a combination of alleles situated on corresponding chromosomes. Biological tests and not observations are the only determiners. A genotype example can be the genes responsible for traits such as a person's shoe size, voice, eye color, hair color, and even diseases.
There are six types of genotype in human beings, and they result in some of the physical characteristics of a person. They are distinguished based on the alleles that a person has. These are:
Relationship between blood types and genotypes
Typically, a blood test is conducted to determine whether the A or B characteristics are present in a blood sample. A blood test alone cannot determine either type A or type B. A blood type A individual has at least one copy of the A allele, but they could also have two copies. Such a person can have AA or AO.
A blood type of type AB or O is more informative when determining the group. A person with blood type AB automatically has both the A and B alleles, and therefore, it is AB. A person with blood type O, on the other hand, has neither the A nor the B allele, and the resultant is OO.
Importance of knowing your genotype
The knowledge of hemoglobin genotype is relevant when choosing a life partner to avoid compatibility issues that may result in devastating effects relating to conception. This is why it is essential to ask questions such as how many types of genotype are there and what is their compatibility.
People with sickle cells experience episodes of severe pains in body parts where oxygen flow is compromised because of blockage in the blood vessels. People with genotype AA are safe to marry individuals with any of the others. AS is compatible with AA, AS, and AS, AS and AC are too risky since two sickle cells should avoid conception. Below is a comprehensive compatibility chart:
AA + AA = AA, AA, AA, AA (Excellent)
AA + AS = AA, AS, AA, AS, (Good)
AA + SS = AS, AS, AS, AS, (Fair)
AA + AC = AA, AA, AA, AC. (Good)
AS + AS = AA, AS, AS, SS, (Very Bad)
AS + SS = AS, SS, SS, SS, (Very Bad)
AS + AC = AA, AC, AS,SS. (Bad; Advice needed)
SS + SS = SS, SS, SS, SS, (Very Bad)
AC + SS = AS, AS, SS, SS, (Very Bad)
AC + AC = AA, AC, AC, SS. ( Bad; Advice needed)
Difference between genotype and phenotype
Even though the two might sound the same and are related, they mean different things. While genotype refers to the set of genes in the DNA of an organism responsible for a particular trait, on the other hand,phenotype,is described as the physical expression, or characteristics of that trait. Phenotypes can be determined just by observing things such as height, hair color, and eye color, and so on.
Types of sickle cell genotype
Sickle cell anemia is caused by a gene mutation of the red blood cells that makes them be shaped like a crescent moon. This gene is inherited, so it means one can only have the disease if both parents transfer the genes to a child. If a child has only one of the genes, he/she is said to have sickle cell traits. Here are the common types of sickle cell disease:
- Hemoglobin SS: It is the most common of the sickle cell diseases and is caused by a child inheriting copies of the hemoglobin S gene from the father and mother.
- Hemoglobin SC: Not as common as the first one and occurs when a child inherits the hemoglobin C gene from one parent and hemoglobin S gene from the other parent.
- Hemoglobin SB+ thalassemia: The disease inhibits beta-globin gene production, and the subsequent reduction in the production of beta proteins results in a reduction of the size of the red blood cells.
- Hemoglobin SB 0 thalassemia: This disease is sporadic and is caused by the beta-globin gene.
Genotypes are significant to human beings as they determine such things as resistance to diseases, reaction to certain drugs, development of immunity, and the features that shape an individual. The types of genotype influence your phenotype, thus having an impact on your traits. You should, therefore, make a point of discovering your type to avoid compatibility issues when picking a partner.
Disclaimer: All the information contained in this article is not implied or intended to be a substitute for any professional medical advice, diagnosis or treatment. All content inclusive of images, graphics, and information contained on or available through this page is for general information purposes.
READ ALSO: Best blood group compatibility for marriage
Source: Yen Ghana