Important Reasons Why You Should Know Your Genotype and Blood Group


Blood group and genotype are two important factors that determine the overall health of an individual; it tells a lot about the person’s DNA, physiology and sometimes behaviour.


Blood group is a method of classification of the blood which is based on the absence or presence of antibodies of inherited antigenic substances on the surface of the erythrocytes (red blood cells); while genotype is the part of the genetic makeup of a cell, an organism or individual which determines one of its characteristics.

Reasons why you should know yours

  • It guides one when choosing a marriage partner; this will avoid giving birth to children with health complications like sickle cell anemia
  • It helps in emergency situations where a quick blood transfusion is needed and this will prevent health complications like incompatibility, blood clump/clot and death.
  • It helps in predicting disease risk; different blood groups have their risk of diseases for example, blood group AB, A and B have increases risk for blood clots and individuals with these blood groups have 40% risk of having deep vein thrombosis and blood clots in the lower legs that can be dangerous and they also have increased risk of heart disease.

Individuals with blood type A have a higher rate of fertility but an increased risk of stomach cancer, individuals with blood type AB and B have higher risk for pancreatic cancer and individuals with blood type o has the lowest risk of stroke. Mosquitoes are attracted to blood type O.

Knowing your blood group can help you to know the risk associated with your blood type and you will know how to conduct yourself so that you can prevent these diseases from happening to you.

  • It helps you to know the nature of your body, system and how it functions; you will know what to embrace and what to avoid.
  • You will be able to help others when you know your blood group; when a call is made for a specific blood type to potential blood donours to help accident victims or other medical emergency, you can donate easily without going through test.
  • It makes one improve diet and exercise; when a person knows his or her blood group and the risk involved, it can make them to pick up healthy lifestyle like healthy dieting and regular exercises to cut down the risk of the diseases. Some even eat food based on their blood type to make then healthy; this is called “the blood type diet” and it is believed that the food that you eat can react with your blood type.

Those with type O blood are advised to eat a high protein diet with lean meats and light on grains and type A is advised to avoid meat and take on the vegetarian diet (mostly fruits, vegetables and beans).  This blood type dieting is believed to have helped many especially with weight loss and increased energy.

There are even exercises good for specific blood types; individuals with blood type O can handle strenuous exercises, type A can handle tai chi and yoga, type AB gets the best of both worlds and are good in both demanding and calming activities like running and meditation. These blood groups can gain from other activities but they react best to the exercises that suit them.

The ABO grouping system and the Rh factor

There are over 20 different blood group systems but the ABO method of grouping and the RhD blood group system is the most important and most common of all; in this system of grouping, there are four ABO blood groups and they are blood groups A, B, AB and O. They differ based on the presence of different antigens on the surface of the red blood cells.

An individual with blood group A has the A antigen, an individual with blood group B has the B antigen, an individual with the blood group AB has both A and B antigens on the surface of their red blood cells and those with the blood group O have neither of the antigen present.

Individuals who have the D antigens on the surface of their red blood cells are said to be RhD positive (that is they have the rhesus factor or are rhesus positive) while those lacking the D antigen on the surface of their red blood cells are said to be rhesus negative.

What are the complications that can arise from blood group?

Blood clumping: Individuals can only receive donated blood from someone with the same blood group; except for individuals with blood group O that are rhesus negative, they are known as the “universal donour”. When an individual receives a different blood group apart from his or O negative, it can lead to clumping or formation of clots and this can lead to death.

The rules for blood donations are:

Type O: Individuals with this blood type can donate blood to anyone because they have no antigens but they can only receive blood from O donours because any other blood with antigens will be seen as foreign and the body will attack it.

Type A: Individuals with this blood type can donate blood to individuals with the blood group A and AB and they can only receive blood from individuals with type A and type O.

Type B: People with this blood group can donate blood to individuals with the blood group B and AB and they can receive blood from only donours with B and O blood groups.

Type AB: People with this blood group are known as the “universal recipients”; they can receive blood from blood of any type but they can only donate to AB.

As stated earlier, blood groups are further organized by the Rh factor also known as the Rhesus factor which is characterized by the presence of the D antigen on the surface of the red blood cells. It is divided into two:

Rh positive: Individuals that are Rh positive have the D antigens on the surface of their red blood cells; they can receive both Rh positive and Rh negative blood.

Rh negative: Individuals that are rhesus negative lack the D antigen and they can receive blood from only Rh negative donours.

Pregnancy complications: Complications in pregnancy like miscarriages can occur if the mother is rhesus negative and the child is rhesus positive; although the first pregnancy can be safe but during the second pregnancy the body has already become sensitize and it will attack the fetus because it sees it as a foreign body, this happens when the blood of the mother and baby mixes which is very rare.

When the mother’s body recognize the Rh protein; it sees the fetus as foreign and rejects it. Before now, it was not advisable for a rhesus positive man to marry a rhesus negative lady but there are treatments that can be used to desensitize the woman’s body which leads to safe pregnancy, in most cases, an anti-D immunoglobulin shot is given to the woman.

Complications will not arise if the both the man and the woman are rhesus negative; or in very rare cases if the baby is rhesus negative and the mother is rhesus negative but the father rhesus positive. There won’t also be complications if the mother is rhesus positive and the child is rhesus negative.

Pregnancy complication can also be caused by blood incompatibility; this can lead to problems in an unborn child like jaundice or still birth. It can occur when a mother has the O blood group and the baby has A, B or AB blood type from the father, there will be a 20% incompatibility rate. Complications can also happen if the woman has A blood group and the man has either B or AB blood group, or if the woman has B blood group and the man has A or AB blood group. This is known as ABO incompatibility.

What about genotype?

Genotype is the complete heritable genetic identity of an individual; it can also refer to a particular gene or set of genes that an individual carries, it also tells the genetic makeup of an individual or the information contained within the genes.

Alleles are what distinguish genotype among individuals and they are six different genotypes in humans; they are AA, AS, AC, SS, SC and CC.

Like blood group; it is very important for one to know their genotype because not every genotype is compatible, it can lead to health complications in the new born like the sickle cell anemia.

AA can marry anybody of their choice even if it is SS; while AS has to be careful, they can’t marry AS or SS and SS can only marry AA. AS are carriers of sickle cell anemia but they are not sicklers, SS are the ones with sickle cell anemia and SC are the ones with sickle cell disease.

Below is a guide when dealing with genotype issues in marriage.

  • AA + AA = AA, AA, AA, AA
  • AA + AS = AA, AS, AA, AS, 
  • AA + SS = AS, AS, AS, AS,
  • AA + AC = AA, AA, AA, AC.
  • AS + AS = AA, AS, AS, SS,
  • AS + SS = AS, SS, SS, SS,
  • AS + AC = AA, AC, AS, SS.
  • SS + SS = SS, SS, SS, SS,
  • AC + SS = AS, AS, SS, SS,
  • AC + AC = AA, AC, AC, SS.

Note that SS, SC and CC are sickle cell diseases while AS and AC are carriers.



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