The total number of genes passed from parents to kids is known as a genotype. An alternative definition of a genotype is the entire collection of heritable genes that can be passed from one parent to the next. These genes aid in encoding particular traits and qualities that an organism can physically express (phenotype). An organism’s genotype is made up of all of its genetic components. An individual’s alleles or variations in a specific gene or genetic region are also referred to as the genotype. The number of copies of each chromosome found in that species, also known as ploidy, determines how many alleles a person can have for a certain gene.
In diploid organisms like humans, there are two complete sets of chromosomes, which means that each person has two alleles for each gene. Homozygous refers to a genotype when both alleles are the same. Heterozygous refers to a genotype when there are two distinct alleles.
Phenotype, the observable qualities, and attributes of an individual or creature, is influenced by genotype.
Genetics can have varying degrees of influence on phenotype depending on the trait. For instance, a pea plant’s petal color is solely determined by genotype. Depending on the alleles present in the pea plant, the petals can be either purple or white.
Other features, however, are only somewhat influenced by genotype. Because they are impacted by additional elements, such as environmental and epigenetic influences, these traits are frequently referred to as complex traits. Because appearance and behavior are influenced by environmental and growing situations, even people with the same genotype do not all look or behave the same. Similar to how not all organisms with similar appearances share the same genotype.
History
The word genotype is derived from the Latin word generis, which has a very similar meaning to the word genus and derives from the root geno, which means lineage or birth. It also contains the word typos, which is related to the verb “typtein,” which means to hit and meaning to mark, print, or type. Wilhelm Johannsen, a scientist from Holland who developed the distinction between the genotype and the phenotype, proposed and used the term. These terms were put forth and are crucial for identifying the difference between an observer who looks at DNA and someone who determines an organism’s phenotype by looking at its outward appearance.
Characteristics of the genotype
Among the main characteristics we can mention the following characteristics:
- They are a set of genes that characterize species, whether plant or animal.
- They have a DNA format and humans receive it through inheritance from their parents.
- The genes that are in charge of transmitting the characteristics of heredity are always in the nucleus of the cell.
- It manifests on the external part and includes all the physical characteristics that individuals possess.
- It can be distinguished when the DNA is observed.
- The phenotype is responsible for manifesting hereditary diseases.
Blood type genotypes and their characteristics
A person’s unique characteristics are determined by a confluence of alleles located on related chromosomes. The only criteria are biological testing, not observations. The genes that determine a person’s shoe size, voice, eye color, hair color, and even certain diseases are examples of genotypes.
To ascertain if the A or B features are present in a blood sample, a blood test is typically performed. Type A or type B cannot be identified by a blood test alone. An individual with blood type A has at least one copy of the A allele, but they may have two copies as well. A person like this could have either an AA or an AO blood genotype.
Humans have six different genotype types, and these genotypes influence aspects of a person’s physical traits. Based on the alleles that a person possesses, they can be recognized. What are the six genotypes of blood types? They are:
- AA
- AS
- SS
others are:
3.SS
5. SC
6. CC
What Is AA Genotype?
Having genotype AA means that you inherited the “A” gene from your parents. It is also the homozygous dominance of AA genes in your DNA.
The alleles in the pair, whether they are both dominant or both recessive, are the same, making the pairs “AA” and “aa” homozygous. Contrarily, the allelic pair “Aa” is referred to as “heterozygous.”
Characteristics Of AA Genotype
People with the “A” genotype have certain features that distinguish them from other individuals.
Such features include:
- More prone to malaria attacks.
- Weaker immune responses to viral infections(2).
- Can marry any other genotypes without the fear of haematological disease.
Combability of AA genotype
AA can marry any one as they have no Sickle cell Trait. Bearers of this genotypes are the safest
AS Genotype
Red blood cells with genotype AS (defective hemoglobin) adapt and cling to the parasitized red cells more readily than red blood cells with genotype AA (normal haemoglobin). An aberrant type of hemoglobin can be found via hemoglobin electrophoresis.
A carrier or sickle cell trait is another term for the AS genotype. It occurs when you have a sickle cell hemoglobin and one normal gene.
AS genotype Characteristics
Just like other carriers, the AS genotype is not a sickness and they don’t show symptoms. However, they pass the trait to their offspring.
Options for AS genotype couples
Playing with sickle cell illness might be difficult for couples with AS (SCD).
Even if it’s never a bed of roses, they still have some options. They consist of;
1. Genetic testing throughout pregnancy.
This is a procedure to check for sickle cell anemia in an unborn child’s genetics. The examination looks for anomalies in the developing child’s hemoglobin. Prenatal genotyping testing is where you may get additional information about the test.
2. in vitro fertilization (IVF)
IVF is a fertility-assistance method designed for couples who are having trouble getting pregnant. Additionally, it can assist AS couples in having non-SS offspring.
IVF includes fertilizing an egg in a test tube with the sperm or egg of a non-carrier (AA) before inserting the embryo into the mother.
3. Genetic pre-implantation testing (PGD)
Similar to IVF, PGD. It involves egg and sperm fertilization in a petri dish. Before cell biopsy, they grow for around 4 days inside the dish.
During a biopsy, SS is eliminated and non-sickler cells are sent to the mother.
4. Adopt infants:
Couples with AS who don’t want to take a chance of having a sickler might consider adopting children. Although some shame may come from the families, being in a pair is still preferable to having sickles.
5. Childless marriage:
While this may be a difficult option, some couples may still opt-in for it.
Childless marriages may still work for AS couples that don’t want babies.
SS Genotype
The hemoglobin genotype that results in sickle cell anemia is referred to as SS. It consists of two sickle cell alleles, or the SS genotype (S). Each parent contributes one allele to each child. The S allele exhibits some malaria resistance. Two globin proteins combine to create hemoglobin. Hemoglobin A is the name given to the wild-type hemoglobin. Red blood cells made with hemoglobin A have a typical disk shape and are adaptable enough to pass through tiny blood channels. Hemoglobin S is produced by the S allele. Crescent-shaped red blood cells are created by hemoglobin S. These stiff and sticky red blood cells are present. The blood flow is obstructed as a result of their clumping together. In addition to bone deterioration and priapism, this leads to pain crises and painful, protracted erections. The condition in question is known as sickle cell disease.
Symptoms of SS Genotype
The symptoms of the sickle cell disease are :
- Excessive fatigue from anemia
- Fussiness in babies
- Bedwetting from associated kidney problems
- Jaundice
- Frequent infections
- Swelling and pain in hands and feet
- Pain in chest and back
- occasional attacks called crisis
Characteristics of SS Genotype
Sickle cell disease is characterized by symptoms like:
- Anemia: This is a condition when there are insufficient red blood cells in the blood due to red blood cells dying too soon.
- Due to the restriction of blood flow to the hands and feet, limbs have become swollen.
- Frequent infections in cases where the spleen becomes damaged, leaving the individual vulnerable to infections
- Delayed growth caused by the inability of red blood cells to effectively transport nutrients and oxygen
Study this table below carefully:
AA + AA = AA, AA, AA, AA (Excellent) AS + AC = AA, AC, AS,SS. (Bad; Advice needed) AA + AS = AA, AS, AA, AS, (Good) SS + SS = SS, SS, SS, SS, (Very Bad)
AA + SS = AS, AS, AS, AS, (Fair) AC + SS = AS, AS, SS, SS, (Very Bad)
AA + AC = AA, AA, AA, AC. (Good)
AS + AS = AA, AS, AS, SS, (Very Bad)
AS + SS = AS, SS, SS, SS, (Very Bad)
AC + AC = AA, AC, AC, SS. ( Bad; Advice needed)
Combability of SS Genotypes
Those with Sickle Cell Traits can’t marry any other genotype Except AA. If they marry outside the specified genotype, they risk having kids that would be sickle cell carriers and thereby inflicting suffering an d pains to their unborn children.
