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THE ROLE OF GENOTYPE, PHENOTYPE AND RHESUS FACTOR IN MARITAL CHOICES

Making marital plans and choices goes beyond the physical and behavioral characteristics of the person you would want to marry or the type of wedding you would love to have. While these aren’t inconsequential, there are more important factors you need to take into consideration before walking down the aisle. These include genotype and rhesus factor compatibility.

The awareness of genotype compatibility has been staggering lately, unlike in the grey past where people were forced to live with the consequences of ignorance. But regardless of the numerous campaigns going on, there is the need to shed more light on the lesser-known factors of the compatibility spectrum.

Take for instance, when it comes to enlightenment and awareness, Rhesus compatibility continues to get the short end of the stick compared to its counterpart (genotype compatibility). But what is the fuss about these compatibilities in the first place? Well, You are about to find out!!  

 

WHAT IS GENOTYPE?

Every individual has a genetic makeup made up of genes. Genes determine an organism’s appearance, behavior, and even survival. In biology, a gene is defined as a portion of DNA (deoxyribonucleic acid) that encodes biological instructions that make cells produce a specific protein(enzyme) which in turn triggers a particular action in the organism.

The combination of DNA and genes makes up the human chromosome. These chromosomes carry strands of DNA with lots of genes. The DNA carries important genetic information, and it is passed down from parent to offspring during reproduction. The complete or entire set of genetic information (DNA) in a human is known as the Genome.

Genes are made up of four nucleotide bases namely ; Adenine(A), guanine(G), cytosine(C), and thymine (T). This collectively makes up the letters ACGT. The different combinations of these letters or chemical bases differ in individuals and give different characteristics to people.

An individual with a combination of ATGCCT may have black hair, while another individual with a combination of ATTCGC may have brown hair. What this means is that, a gene can exist in different forms. These different gene variations are known as alleles. The combination of these alleles for a specific gene trait in an individual is known as Genotype. Genotype examples include hair color, eye color, height, certain behaviors, and diseases.

 

THE HEMOGLOBIN GENOTYPE

The genes also encode hemoglobin content that gives rise to different hemoglobin genotypes. The human blood is predominantly made up of a set of cells called red blood cells (RBCs). These RBCs are made up of hemoglobin that gives the blood it’s characteristic red color. It is also responsible for transporting blood from the lungs to all body tissues. Basically, the hemoglobin is the most important component of the red blood cells.

There are three major types of hemoglobin which are Hemoglobin A, Hemoglobin S and the very rare Hemoglobin C. Each person has a pair of these hemoglobin in their blood, which is inherited from both parents. The pairing of these hemoglobin types gives rise to the list of genotypes we have today. These include :

AA

AS

SS

AC  

SC

CC

The genotypes SC and SS are identified as sickle cell disease, which is a hemoglobin disorder. The genotype AS is defined as having a sickle cell trait, while the AA genotype is defined as having no hemoglobin disorder. These disorders occur due to mutations in the genes that encode the hemoglobin types.

The hemoglobin has two alpha protein chains and two beta-globin chains. An unusual shift or substitution in the structure or combination of these genes can result in sickle cell disease. It manifests in an individual when they inherit copies of the Hemoglobin S genes from both parents resulting in an SS genotype, or when they inherit one copy of the Hemoglobin S gene from one parent and a copy of Hemoglobin C gene from the other parent, resulting in the SC genotype. So how does this relate to marital choice?

GENOTYPE COMPATIBILITY, WHY DO YOU NEED TO KNOW

It is of utmost importance to know your genotype and that of your partner before deciding to exchange vows. This is imperative because of the recessive hemoglobin disorder called the sickle cell disease which we explained above. The sickle cell disease is a very serious and life-threatening condition that is quite prevalent in sub-Saharan Africa. The disease is characterized by a shortage of blood to different parts of the body following the distortion in the shape of the RBCs.

The RBCs are naturally shaped as discs that enable them to travel through different blood vessels, no matter the size. However, when this disease occurs, the RBC’s take on an abnormal crescent shape that resembles a sickle. The sickle-shaped RBCs find it difficult to navigate blood vessels and are prone to sticking and getting trapped in some of these vessels, which prevents efficient blood flow throughout the body.

This invariably leads to severe pain and tissue damage. This blockage also prevents the RBCs from getting and transporting sufficient oxygen. Subsequently, the bone marrow will find it difficult to produce RBCs, resulting in anemia. A sickle cell patient with anemia will occasionally need blood transfusions to remedy their health.

The effects of sickle cell disease are devastating for both parent and child. The child is subjected to a health burden for the rest of their lives with continuous trips to the hospital. The pain is quite severe and it manifests in every part of the body where there is a shortage of blood. They are also susceptible to frequent infections, excruciating bone pains, excessive fatigue from anemia, jaundice among other debilitating symptoms. This disease also asserts a financial and emotional strain on the parents.

No one would deliberately want to live through this nightmare either as a child or as a parent. Although there is proven treatment for sickle cell disease which is a bone marrow transplant (BMT), it is quite expensive and comes with several risks and complications. So the best remedy for this disease will be prevented. Fortunately, it is highly preventable since it is a known inheritable disease.

In clear terms, you can avoid falling victim or parenting a child with a sickle cell disorder by marrying a person whose genotype is compatible with yours. In addition to this, you will also help to reduce the prevalence and high statistics of this disease. Below is a compatibility chart that can point you in the right direction when making marital and conception choices with regard to genotype.

Also read –Benefits of celibacy or abstinence from sex

GENOTYPE COMPATIBILITY CHART

Genotype (Partner A) Genotype(Partner B) Possible genotype of offspring Compatibility Remark
AA AA AA, AA, AA, AA Recommended for marriage
AA AS AA, AS, AA, AS Recommended for marriage
AA SS AS, AS, AS, AS Recommended
AS AS AA, AS, AS, SS Not recommended
AS SS AS, SS, SS, SS Not recommended
SS SS SS, SS, SS, SS Not recommended
AA SC AS, AC, AS, AC Recommended
AA CC AC, AC, AC, AC Recommended
AS SC SS, AS, AC, SS Not recommended
AS AC AC, AC, SC, SC Not recommended

From the table above, it is clear that a person with genotype AA can marry a person with any genotype without the risk of parenting a child with sickle cell disease. But this does not apply to people with other genotypes. An AS genotype individual is better off marrying a person with the AA genotype.  

Conceiving a child with a person with a similar genotype or who has a trait of the sickle cell such as AC can increase the risk of parenting a child with sickle cell. They should also steer clear of marrying people with the genotype SS, as chances of parenting a sickle cell child are high.

People with the SS and SC genotype are better suited to people with genotype AA. The combination of SS and AS or SC can result in a sickle cell formation. And the worst genotype combination will be that of SS and SS or SS and SC. This is highly not recommended as it is tantamount to a sickle cell disaster.

You can determine your genotype by taking a blood type test at the hospital. You and your partner can take the test together to rule out all possible doubts.

 

GENOTYPE  VS PHENOTYPE

A phenotype is defined as the outward and observable characteristics of an individual which includes appearances and behavior. The major difference between genotype and phenotype is that genotype is inherited from a person’s parents while phenotype is not. The genotype does not directly determine the phenotype, but it can assert a considerable influence. In essence, the phenotype results from the interaction of an organism’s genotype with its the environment.

For example, the genes determine the amount of melanin produced by each individual, but prolonged exposure to the sun’s ultraviolet rays in sunny climates can make the skin look darker than natural. Another example is a person who loves to cook, this does not mean that this person has genes that encode cooking.

And to answer a frequently asked question, phenotype does not influence marital choices the way genotype does. For instance a person’s skin color might not be the direct result of their genotype and even if it is, it wouldn’t hurt to have children who look like your loving partner. In summary,  you can maintain a happy and blissful marriage regardless of your outward physical characteristics.

Also Read – Domestic Violence: Who is affected and how can it be stopped?

BLOOD GROUP AND RHESUS COMPATIBILITY

It is highly recommended that prospective couples should know their blood group before taking the big step. This is necessary for the event of an emergency and to prevent problems during pregnancy.

The red blood cells that transport oxygen carry antigens that can trigger an immune response. These antigens determine the blood group of an individual. There are four major blood groups identified by the letters A, B, O and AB. In addition to these, there is the presence of a protein called Rh factor that maybe either present (+) or absent (-), in each of these blood groups. This subdivides the blood groups into; A+, A-, B+, B-, O+, O-, AB+, and AB-.

The Rh factor and the blood groups are both inherited from a person’s parents. Being either Rh positive or Rh negative does not affect your general health in any way, but it can lead to a problem during pregnancy known as Rh incompatibility.

Rh incompatibility is a pregnancy condition that results when the expectant mother has Rh-negative blood while the baby has Rh-positive blood. The combination of these two different bloods, one with protein and one without, can lead to the development of a disease called hemolytic anemia or rhesus disease in the baby.

A woman’s blood hardly mixes with that of her baby’s during pregnancy, but a minimal amount of the baby’s blood can combine with the mother’s during delivery. This will pose a problem if the baby has an Rh factor and the mother doesn’t.

In this case, the mother’s body will consider the baby’s Rh+ blood a foreign substance and produce antibodies against it. The Rh antibodies produced by the mother’s body can bypass the placenta and infiltrate the baby’s red blood cells which can subsequently lead to hemolytic anemia. 

Hemolytic anemia is characterized by a shortage of red blood cells. In this condition, red blood cells are destroyed rapidly before the body has a chance to replace them. And since red blood cells transport oxygen to all parts of the body, a shortage in these cells means the newborn baby will oxygen-deficient (This can lead to severe complications) .

This condition can be fatal. Symptoms of rhesus disease include jaundice and heart failure. Jaundice is characterized by yellow eyes and skin. It occurs when red blood cells die and release hemoglobin into the blood, which is then broken down into bilirubin that gives the skin and eyes a yellow like color. Heart failure from rhesus disease occurs when there is fluid accumulation In different parts of the baby’s body. This can be fatal to the baby at birth or shortly after birth.

Rh incompatibility does not usually affect first pregnancies, as the baby is born before most of the mother’s antibodies are formed. However, these antibodies remain in the body and are bound to cause problems in second or subsequent pregnancies where the baby is Rh-positive. A blood transfusion or miscarriage can also expose a woman to Rh-positive blood.

Fortunately, problems with Rh incompatibility can be prevented with proper prenatal screening. Screening tests can reveal the RH group you and your baby belong to, Wheather positive or negative. Usually, an injection called globulin is prescribed to stop the body from making antibodies when the mother is carrying a child with Rh factor.

Early prenatal care can avail your doctor the opportunity of knowing about your risk for Rh incompatibility. If found to be at risk, your doctor will monitor you and your baby, administer the right medication when needed, and watch out for the signs of rhesus disease in your newborn.

THE RH FACTOR AND MARRIAGE

The Rh factor is generally not an obstacle for intending couples. Although an Rh-negative woman who marries or conceives a child with an Rh-positive partner is at risk of Rh incompatibility because the protein is passed from parents to offspring through genes.

In light of this, you and your partner have more than a 50% chance of conceiving a child with Rh-positive blood. However, this problem can be solved by taking screening tests to determine you and your partner’s blood group and rhesus factor category.When a test reveals your Rh group, you can take necessary precautions during pregnancy to avoid birthing a child with rhesus disease.

Also, hemolytic anemia in newborns can be treated with drugs and blood transfusions. In moderate cases, the baby can be given a drug called erythropoietin and iron supplements to activate the production of red blood cells. In severe cases, a blood transfusion through the umbilical cord may be required.

In some really severe conditions, where the baby Is almost due for delivery, labor may be induced for the doctor to begin immediate treatment. A newborn baby with severe rhesus disease will have to undergo a blood exchange transfusion where the baby’s blood is slowly drained and replaced with fresh blood from a donor. Newborns with jaundice are treated with special lights to reduce bilirubin levels in their blood, this is necessary as high levels of this compound in the blood can cause brain damage.

In summary, it is imperative that you and your partner take a blood test to determine your blood group and rhesus factor to avoid possible problems during pregnancy. Getting a test done will slim down your chances of giving birth to a baby with rhesus disease.

GENOTYPE, PHENOTYPE, AND RHESUS FACTOR  TEST 

Getting tested for blood type, group and rhesus factor is the key to avoiding a marriage that is rife with unhappiness and complications. There are certain genotype combinations that are not suitable for marriage and conception.  You will be doing yourself a world of good when you marry a partner whose genotype is compatible with yours. Although the blood group and rhesus factor have lesser conception consequences, they also shouldn’t be neglected.

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