Should This Dog Be Called Spot? Trust The Answer

Yes, there is now another course that I prefer

Yes, there is another university now that I prefer

Yes, because I expect to beat my predicted grades

Yes, because I expect to miss my offer

I’m not sure and will make a decision on results day

No, I don’t intend to

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No two people are the same. People might have some form of resemblance, look alike, act alike, maybe talk alike, but in reality no two people are absolutely the same.

The genotype is the biological coding that ensures this specificity, uniqueness and individuality. DNA (deoxyribonucleic acid) contains the instruction manual that directs the formation of our genetic as well as physical traits.

Intended couples should know and share information about each other’s blood genotype and blood type, as this can serve as an important predictor of the genotype, quality of life, and overall health of the offspring.

What is blood genotype?

A blood genotype indicates the genetic composition of a person’s blood as a whole.

Typically there are five (5) different types of blood genotypes. They are AA, AS, AC, SS and SC. While the first 2 pairs (AA & AS) are normal, AC is rare and the last two (SS, SC) are irregular and abnormal, often causing sickle cell anemia. Sickle cell anemia occurs when a person’s blood cells are deformed and shaped abnormally, potentially blocking blood flow, causing pain and damage to vital organs.

Normally, red blood cells are round and flexible and can move easily through blood vessels, but in sickle cell disease, red blood cells are sickle-shaped. These rigid, sticky sickle cells can get stuck in small blood vessels, slowing (or blocking) blood flow and oxygen delivery to parts of the body.

How can knowing your blood genotype improve your quality of life?

Blood genotype (both yours and your partner’s) is a key component to consider before making the decision on a life partner. It’s key because a genotype from father and mother ultimately crosses to determine that of the offspring. Arming yourself with the right genotype compatibility information can help you make the best quality of life decision when it comes to marriage and conception. This can help you stave off the devastating effects of sickle cell disease and thereby improve your quality of life.

Which blood genotypes are compatible?

The AA genotype has the best compatibility ratio. A person with the AA genotype can choose a life partner from virtually any other genotype category with an extremely low probability of having sickle cell offspring. Some research also shows that while the AA genotype is the best tolerated, it is also the most susceptible to malaria. So if you have the AA blood genotype, it’s wise to minimize your exposure to mosquitoes and take other malaria prevention strategies seriously.

The AS genotype is most compatible with the AA. A genotypic mating of AS with AS or AS with AC carries an increased chance of sickle cell offspring. Similarly, mating between AS and SS or AC and SS is equally risky and not advisable, while mating two sickle cell individuals will almost certainly result in sickle cell offspring.

AA + AA = AA, AA, AA, AA (excellent)

AA + AS = AA, AS, AA, AS, (good)

AA + SS = AS, AS, AS, AS, (appropriate)

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. (Poor; advice needed)

Is there a cure for abnormal blood genotypes?

Until the early 1980s, sickle cell disease was considered debilitating and incurable. However, recent research shows that specialized bone marrow or stem cell transplants can be used to cure the disease. A bone marrow transplant is the only known cure for sickle cell disease. It involves replacing the abnormal stem cells found in one bone marrow with healthy cells from a suitable donor (usually a brother or sister). However, the risks associated with this procedure are high and therefore the procedure is rarely performed, especially in third world countries.

See also: diabetes

What are blood types?

Blood type is a function of heredity. This means that it is passed from parents to offspring. It generally refers to the body of antibodies (the body’s natural defences), antigens (substances that cause the immune system to produce antibodies against them) and other molecules present on the surface of red blood cells.

There are currently over 35 blood groups recognized by the ISBT (International Society of Blood Transfusion), but only 4 are common. You are the:

blood group A

blood group B

Blood group AB

blood group O

In some rare situations, red blood cells can possess a unique substance known as Rhesus factor (Rh factor), also known as RhD antigen. When a red blood cell tests positive for RhD, it simply means the antigen is present. Conversely, a negative RhD test means that the antigen is missing.

Why it’s important to know your blood type compatibility

Precise knowledge of your blood group is required before any type of blood transfusion. First, the donor’s blood type must be identified to establish compatibility with the recipient’s blood type. If this process is not done carefully and prudently, the simplest blood transfusion can result in complications that can turn a normally harmless procedure fatal.

For example, a type A blood group has some type B antibodies that occur naturally. If a type A recipient is transfused with blood from a type B donor, the anti-type B antibodies cause intravenous agglutination of the type A recipient’s blood.

Conversely, a type B recipient transfused with blood from a type A donor agglutinates intravenously due to type A antibodies in the type B red blood cells.

Below is a table detailing blood group compatibility.

Recipient Blood Type Compatible RBC Types Compatible Plasma Types A+ O-,O+,A-,A+ O-,O+,AB-,AB+ A- O-,A- O-,O+,AB-,AB+ AB+ O-,O+ ,A- ,A+,B-B+,AB-,AB+ AB-,AB+ AB- O-,A-,B-,AB- AB-,AB+ B+ O-,O+,B-,B+ B-,B+, AB-, AB+ B- O-, B- B-,B+,AB-,AB+ O+ O-, O+ O-, O+, AB-, AB+ O- O- O-,O+,AB-,AB+,A- ,A+ B+,B- compatible blood types

To schedule a test or learn more about your genotype and blood type, contact us.

Dominant and recessive genes

Learning Outcomes To know what it means when a gene is dominant. Understand why sex-linked gene dominance sometimes doesn’t matter

Have you ever wondered why some people have blue or brown eyes? The coloring of blue and brown eyes is an example of different versions of a gene. Different versions of a gene are called alleles. Alleles can be considered dominant or recessive, with dominant being the trait that is observed or exhibited and recessive being the trait not seen.

Dominant alleles are considered uppercase letters; for example B. Recessive alleles are considered lowercase of a letter; b. For a person to exhibit the dominant trait, one of the person’s parents must have the dominant trait (that’s a capital letter). Remember that human cells carry two copies of each chromosome, one from the biological mother’s genes and one from the biological father’s genes. Apart from that there are 2 groups of alleles which can be dominant or recessive. If an individual carries a heterozygous set of alleles (both uppercase and lowercase letters of the gene), then the individual displays the dominant trait (i.e., one capital letter is present). For example, the brown eye allele is dominant, B. You need at least one copy of the brown eye allele (B) to have brown eyes. If you have two copies of the alleles that are both dominant, this is called codominance. For example, for flowers, if the dominant trait is red and another dominant trait is white, then the flower will have both red and white since the dominant traits are equally expressed. If a person carries two copies of the brown eye allele, the person would have brown eyes since they are codominant. Recessive alleles are the genes that don’t show the trait. If an individual has one copy of the brown eye allele (dominant) and one copy of the blue eye allele (recessive), then that individual is considered a carrier of the blue eye allele because they would have brown eyes but still have the blue eyes. Eye feature not shown. Recessive alleles only show the traits when the person has 2 copies of the same alleles. This is considered homozygous as it has the same 2 copies of alleles. If a person has 2 copies of the blue eye allele (both recessive) then the person would have blue eyes.

Sex-linked genes are genes that are inherited via the X chromosome. Remember that a biological female carries two sets of X chromosomes (XX) and a biological male carries one set of X and one set of Y chromosomes (XY). If the offspring is a boy, the X chromosome comes from the mother and the Y chromosome from the father. If the offspring is a girl, one of the X chromosomes comes from the mother and the other X chromosome from the father. In some genetic diseases caused by sex-linked genes, for example hemophila, a trait of color blindness, the allele for the disease is recessive. You can recall that recessive traits only appear if they are homozygous (both copies of the alleles are recessive). For a woman to have the disease, both of her X chromosomes must carry the recessively diseased copies of alleles. For a male to have a sex-linked gene, only one copy of the recessive sex-linked gene is required for the male to have the disease. Dominance doesn’t matter in sex-linked genes for XY males. If the mother is a carrier (unaffected but still has the affected trait), her offspring could be affected. Males are more likely to inherit a sex-linked gene because only one chromosome of a diseased trait is needed, regardless of whether the disease trait is dominant or recessive. You can see that sex linked genes are random. Although the father is affected with a dominant trait, only half of their offspring are affected, especially among the girls, since they must inherit one chromosome from the father. The male offspring were unaffected because they had already received a Y chromosome from the father, so they got the unaffected X chromosome from the mother. In this photo, the mother is affected by a dominant trait, but only half of her offspring could be affected. The offspring had a 50% chance of acquiring the affected trait. In an unaffected mother whose carrier is recessive, meaning the disease trait is recessive, only one of the offspring was affected and one is unaffected but carrier. This is an example of how dominance genes don’t matter as it depends on which X chromosome you can get and whether the chromosomes you inherit contain the disease trait which is dominant or recessive. In males in particular, they would only have a 50/50 chance of inheriting a non-disease trait since they can only get the X chromosome from the mother. In females, they have a lower chance of getting a trait because it depends on which chromosome she inherited from her mother, whether it’s dominant or recessive, and which X chromosome she inherited from her father.

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Title: What are dominant and recessive genes? Provided by: Yourgenome

URL: https://www.yourgenome.org/facts/what-are-dominant-and-recessive-alleles

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Title: Sex-Linked Genes Author: Rachel Lam Provided by: University of Minnesota License: CC BY 4.0

The terms dominant and recessive describe the inheritance patterns of certain traits. That is, they describe how likely it is that a certain phenotype will be passed on by the offspring of the parents.

Sexually reproducing species, including humans and other animals, have two copies of each gene. The two copies, called alleles, can differ slightly from each other. The differences can cause variations in the protein produced or change protein expression: when, where and how much protein is made. Proteins affect traits, so variations in protein activity or expression can produce different phenotypes.

A dominant allele produces a dominant phenotype in individuals who have a copy of the allele that can come from only one parent. For a recessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent. An individual with one dominant and one recessive allele for a gene has the dominant phenotype. They are generally considered to be “carriers” of the recessive allele: the recessive allele is there, but the recessive phenotype is not.

The terms are confusing and often misleading

Dominant and recessive inheritance are useful concepts when trying to predict the likelihood that an individual will inherit certain phenotypes, particularly genetic disorders. But the terms can be confusing when trying to understand how a gene specifies a trait. This confusion arises in part because humans observed dominant and recessive inheritance patterns before anyone knew anything about DNA and genes, or how genes encode proteins that specify traits.

The key point to understand is that there is no universal mechanism by which dominant and recessive alleles operate. Dominant alleles do not physically “dominate” or “suppress” recessive alleles. Whether an allele is dominant or recessive depends on the specifics of the proteins it encodes.

The terms can also be subjective, which adds to the confusion. The same allele can be considered dominant or recessive depending on how you look at it. The sickle cell allele described below is a great example.

health tips

Genotype Compatibility

The genotype can be defined simply as the genetic constitution of an individual organism.

This differs from your phenotype, which is a description of your actual physical characteristics. Knowing your genotype is essential before saying “yes” to that handsome man or woman you want to spend the rest of your life with, or if you are in a relationship where there is a possibility of conception.

The issue to avoid with genotype compatibility for intended couples is sickle cell disease (a recessive disease) – a very serious condition with high prevalence rates in sub-Saharan Africa.

types of genotype

The human genotypes are AA, AS, AC, SS. They refer to the hemoglobin gene components on the red blood cells. AC is rare while AS and AC are abnormal.

Genotype Compatibility Chart

Study this table below carefully:

AA + AA = AA, AA, AA, AA (excellent)

AA + AS = AA, AS, AA, AS, (good)

AA + SS = AS, AS, AS, AS, (appropriate)

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. (Poor; advice needed)

Compatible genotypes for marriage are:

AA marries an AA. That fits best. This saves your future children worrying about genotype compatibility.

AA marries an AS. You end up with children with AA and AS, which is good. But sometimes, if you’re not lucky, all the children are AS, which limits their choice of mates.

AS and AS should not marry, there is every chance of having a child with SS.

AS and SS shouldn’t even think about getting married.

And in any case, SS and SS are not allowed to marry, since there is absolutely no chance of having a child with sickle cell disease.

solution

The only thing that can change the genotype is bone marrow transplantation (BMT). It has proven to be the only promising permanent cure for SS, SC and CC; However, it is new, very expensive and cannot be done in any part of Africa. It also comes with some risks.

The AUN Health Center gives health tips

As June 19 marked World Sickle Cell Disease (SCD) Day, as proclaimed by the World Health Organization (WHO), there is a need to know what is going on so people can take precautions to avoid having children born with the disease , a hereditary disease.

The theme of the day for 2021 was “Shine the Light on Sickle Cell” and focused on raising awareness of the disease.

Sickle cell anemia, also known as sickle cell anemia, is a group of disorders that cause red blood cells to become deformed and break down.

It is an inherited group of disorders in which red blood cells crescent and die early, causing a lack of healthy red blood cells to carry oxygen around the body, blocking blood flow and causing pain to the patient, commonly referred to as sickle cell crisis.

Normal red blood cells typically live about 120 days before they are replaced, but in patients with sickle cell anemia, the cells die in 10 to 20 days, leading to deficiency, and without enough red blood cells, the body cannot get enough oxygen, resulting in this leads to pain and fatigue.

Normally, the flexible, round red blood cells move easily through blood vessels, but in sickle cells, the red blood cells are shaped like crescents or crescents. These rigid, sticky cells can get stuck in small blood vessels, which can slow or block blood flow and oxygen to parts of the body.

There is no cure for most people with sickle cell disease, but treatments can relieve pain and help prevent complications associated with the disease, which can last for years or life and require a medical diagnosis, such as laboratory tests or imaging studies.

The condition is caused by a mutation in the gene that tells the body to make the iron-rich compound that makes blood red and allows red blood cells to carry oxygen from the lungs around the body (haemoglobin).

For a child to be affected, both parents must pass on the defective form of the gene, and if only one parent passes the sickle cell gene to the child, the child will have the sickle cell trait.

With one normal hemoglobin gene and one defective form of the gene, people with the sickle cell trait make both normal hemoglobin and sickle cell hemoglobin.

Their blood may contain some sickle cells, but they generally have no symptoms. They are carriers of the disease, which means they can pass the gene on to their children.

Consequently, there is a need to raise awareness of the importance of genotype testing before marriage, as it is the issue of genotype incompatibility that leads to sickle cell disease, with high prevalence rates in sub-Saharan Africa, according to health tips from the AUN Health Center.

The genotype can be defined simply as the genetic constitution of an individual organism.

The human genotypes are AA, AS, AC, SS. They refer to the hemoglobin gene components on the red blood cells. AC is rare while AS and AC are abnormal.

A genotype compatibility table shows this;

AA + AA = AA, AA, AA, AA (excellent)

AA + AS = AA, AS, AA, AS, (good)

AA + SS = AS, AS, AS, AS, (appropriate)

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. (Poor; advice needed)

The compatible genotypes for marriage are: AA marries an AA – who is most compatible, and in this way the couple spares their future children the worry of genotype compatibility.

Also, if an AA marries an AS, the couple will end up with both AA and AS children, which is good, but sometimes, if you’re unlucky, all the children can be AS, limiting your choice of mate.

However, AS and AS should not marry since there is every chance of having a child with sickle cell anemia, while AS and SS should not consider marriage.

And in any case, SS and SS are not allowed to marry, since there is absolutely no chance of having a child with sickle cell disease.

Signs and symptoms, such as periodic bouts of pain called pain crises, which occur when crescent-shaped red blood cells block blood flow through tiny blood vessels to the chest, abdomen, and joints, usually appear around the age of five months, but vary from person to person and over time change of time.

The pain varies in intensity and can last from a few hours to a few weeks, and while some people have only a few pain crises in a year, others have a dozen or more that require hospitalization.

Other symptoms include swelling of the hands and feet caused by sickle-shaped red blood cells blocking blood flow to the hands and feet, and frequent infections as sickle cells damage the spleen, and delayed growth or puberty due to a lack of healthy red blood cells

slow growth in infants and children and delay puberty in teenagers.

There are also vision problems, as tiny blood vessels that supply the eyes can become clogged with sickle cells, damaging the retina, which is the part of the eye that processes visual images — and leading to vision problems.

Doctors often give infants and children with sickle cell disease vaccines and antibiotics to prevent potentially life-threatening infections, such as pneumonia.

It is therefore important to seek immediate medical attention if a child develops a severe fever, unexplained episodes of severe abdominal, chest, bone or joint pain, swelling of the hands or feet, especially if the area is tender, pale skin or nail beds, Yellowing of the skin or unilateral paralysis or weakness of the face, arms or legs.

Some others are confusion; difficulty walking or speaking; sudden visual disturbances or unexplained deafness; or severe headache.

Meanwhile, the only procedure that can change the genotype is bone marrow transplantation (BMT), which has shown promise as a permanent cure for SS, SC, and CC.

However, the BMT is new and expensive.

(NAN)

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If you’ve read about a genetic condition, you may have come across the terms “homozygous” or “heterozygous.” But what exactly do these terms mean? And what are the practical results of being “homozygous” or “heterozygous” for a particular gene?

Clinical Cytogenetics Unit, Addenbrookes Hospital/Science Photo Library/Getty Images

what is a gene

Before we define homozygous and heterozygous, we need to think about genes first. Each of your cells contains very long stretches of DNA (deoxyribonucleic acid). This is hereditary material that you receive from each of your parents.

DNA is made up of a series of individual components called nucleotides. There are four different types of nucleotides in DNA:

adenine (A)

guanine (G)

Cytosine (C)

Thymine (T)

Inside the cell, DNA is usually found bundled into chromosomes (found in 23 different pairs).

Genes are very specific segments of DNA with a specific purpose. These segments are used by other machines within the cell to make specific proteins. Proteins are the building blocks used in many critical functions in the body, including structural support, cell signaling, facilitating chemical reactions, and transport.

The cell makes proteins (from their building blocks, the amino acids) by reading the sequence of nucleotides found in DNA. The cell uses some sort of translation system to use information in DNA to build specific proteins with specific structures and functions.

Specific genes in the body perform different tasks. For example, hemoglobin is a complex protein molecule that carries oxygen in the blood. Several different genes (contained in DNA) are used by the cell to make the specific forms of protein required for this purpose.

You inherit DNA from your parents. Roughly speaking, half of your DNA comes from your mother and the other half from your father. For most genes, you inherit one copy from your mother and one copy from your father.

However, there is one exception that affects a specific pair of chromosomes called sex chromosomes. Because of the way sex chromosomes work, males only inherit a single copy of certain genes.

Variations in Genes

The human genetic code is quite similar: well over 99 percent of the nucleotides that make up genes are the same in all humans. However, there is some variation in the sequence of nucleotides in specific genes.

For example, one variation of a gene might start with the sequence ATTGCT, and another variation might start with ACTGCT instead. These different variations of genes are called alleles.

Sometimes these variations don’t make a difference in the final protein, but sometimes they do. They can cause a small difference in the protein that causes it to work slightly differently.

A person is considered homozygous for a gene if they have two identical copies of the gene. In our example, this would be two copies of the version of the gene beginning with “ATTGCT” or two copies of the version beginning with “ACTGCT”.

Heterozygous simply means that a person has two different versions of the gene (one inherited from one parent and the other from the other parent). In our example, a heterozygote would have one version of the gene beginning with “ACTGCT” and also another version of the gene beginning with “ATTGCT”.

Homozygous: You inherit the same version of the gene from each parent, so you have two matching genes. Heterozygous: You inherit a different version of a gene from each parent. They do not fit together.

disease mutations

Many of these mutations aren’t a big deal and just add to normal human variation. However, other specific mutations can lead to diseases in humans. This is often what is meant when people talk about “homozygous” and “heterozygous”: a specific type of mutation that can cause disease.

An example is sickle cell anemia. In sickle cell anemia, there is a mutation in a single nucleotide that causes a change in the nucleotide of a gene (called the β-globin gene).

This causes an important change in the configuration of hemoglobin. Because of this, red blood cells that carry hemoglobin begin to break down prematurely. This can lead to problems like anemia and shortness of breath.

In general there are three different options:

someone is homozygous for the normal β-globin gene (has two normal copies)

for the normal β-globin gene (has two normal copies) someone is heterozygous (has one normal and one abnormal copy)

(has one normal and one abnormal copy) someone is homozygous for the abnormal β-globin gene (has two abnormal copies)

People who are heterozygous for the sickle cell gene have an unaffected copy of the gene (from one parent) and an affected copy of the gene (from the other parent).

These people don’t usually get the symptoms of sickle cell anemia. However, people who are homozygous for the abnormal β-globin gene do get symptoms of sickle cell anemia.

Heterozygous and genetic diseases

Heterozygotes can get genetic diseases, but it depends on the type of disease. With some types of genetic diseases, it is almost certain that a heterozygous person will get the disease.

With diseases caused by so-called dominant genes, a person only needs one bad copy of a gene to have problems. An example is the neurological disease Huntington’s disease.

A person with only one affected gene (inherited from one parent) will still almost certainly get HD as a heterozygote. A homozygote that receives two abnormal copies of the disease from both parents would also be affected, but this is less common with dominant disease genes.

In recessive diseases such as sickle cell anemia, heterozygotes do not become ill. However, sometimes they can show other subtle changes depending on the disease.

If a dominant gene causes a disease, a heterozygote can manifest the disease. If a recessive gene causes a disease, a heterozygote may not develop the disease or have lesser effects of it.

What about sex chromosomes?

Sex chromosomes are the X and Y chromosomes that play a role in sex differentiation. Females inherit two X chromosomes, one from each parent. So, a woman can be considered homozygous or heterozygous for a specific trait on the X chromosome.

Men are a little more confusing. You inherit two different sex chromosomes: X and Y. Because these two chromosomes are different, the terms “homozygous” and “heterozygous” do not apply to these two chromosomes in males.

You may have heard of gender-linked diseases like Duchenne muscular dystrophy. These show a different inheritance pattern than conventional recessive or dominant diseases, which are inherited via the other chromosomes (so-called autosomes).

Heterozygous Advantage

For some disease genes, it is possible that heterozygosity confers certain advantages on an individual. For example, it is believed that heterozygosity for the sickle cell anemia gene may provide some protection against malaria compared to people who do not have an abnormal copy.

estate

Let’s assume two versions of a gene: A and a. When two people have a child, there are several options.

Both parents are AA : All their children will also be AA (homozygous for AA).

: All of her children will also be AA (homozygous for AA). Both parents are aa: all their children will also be aa (homozygous for aa).

: All their children will also be aa (homozygous for aa). One parent is Aa and another parent is Aa: Your child has a 25% chance of being AA (homozygous), a 50% chance of being Aa (heterozygous), and a 25% chance of being aa (homozygous ) to be.

: Your child has a 25 percent chance of being AA (homozygous), a 50 percent chance of being Aa (heterozygous), and a 25 percent chance of being aa (homozygous). One parent is Aa and the other is aa: Your child has a 50 percent chance of being Aa (heterozygous) and a 50 percent chance of being aa (homozygous).

: Your child has a 50 percent chance of being Aa (heterozygous) and a 50 percent chance of being aa (homozygous). One parent is Aa and the other is AA: Your child has a 50 percent chance of being AA (homozygous) and a 50 percent chance of being Aa (heterozygous).

A word from Verywell

The study of genetics is complex. If there is a genetic condition in your family, do not hesitate to consult a genetic counselor or your doctor to learn what it means for you.

Heterozygous is a term used in genetics to describe when two variations of a gene, known as alleles, are paired at the same place (locus) on a chromosome. In contrast, is homozygous when two copies of the same allele are present at the same locus.

The term heterozygous derives from “hetero” meaning “different” and “zygote” meaning a fertilized egg or zygote.

determine properties

Humans are called diploid organisms because they have two alleles at each locus, with one allele inherited from each parent. The specific pairing of alleles results in variations in an individual’s genetic traits.

An allele can be either dominant or recessive. Dominant alleles are those that express a trait even if there is only one copy. Recessive alleles can only express themselves when there are two copies.

One such example is the genetic inheritance of brown eyes, which are dominant, and blue eyes, which are recessive. If the alleles are heterozygous, the dominant allele would express over the recessive allele, resulting in brown eyes.

At the same time, the person would be considered a ‘carrier’ of the recessive allele, meaning that the blue eye allele could be passed to the offspring even if that person has brown eyes.

Alleles can also be incompletely dominant, an intermediate form of inheritance in which neither allele is expressed completely over the other.

An example of this could be an allele corresponding to darker skin where a person has more melanin when paired with an allele corresponding to lighter skin where there is less melanin. This could create a skin tone somewhere in between.

Punnett Square of the Heterozygous Genotype The Punnett square of the heterozygous genotype is a basic mathematical grid used to represent inherited traits such as eye color or the likelihood of sickle cell disease. As the study of molecular genetics advances, Punnett square remains a useful tool, but within a much broader thinking about gene expression and heterozygous genotype and phenotype.

disease development

Aside from an individual’s physical traits, mating heterozygous alleles can sometimes result in a higher risk of certain conditions, such as birth defects or autosomal disorders (genetically inherited diseases).

When an allele is mutated, a disease can be passed on to offspring even if the parent shows no signs of the disorder. Regarding heterozygosity, this could take one of several forms:

If the alleles are heterozygous recessive, the erroneously mutated allele would be recessive and would not express itself. Instead, the person would be a carrier.

If the alleles are heterozygous dominant, the faulty allele would be dominant. In such a case, the individual may or may not be affected (compared to homozygous dominance, where the individual would be affected).

Other heterozygous pairings would simply predispose a person to a health condition such as celiac disease and certain cancers. This doesn’t mean a person will get the disease; it simply suggests that the person is at higher risk.

Other factors such as lifestyle and environment would also play a role.

Genetic Research Using Lineage Parents Often people wonder who has the stronger genes, the mother or father in a couple. The answers are complex and depend on how you define stronger; For example, some genes are only inherited from one parent or the other. Much of the research focuses on genetic contributions from the “parents of origin”.

Single Gene Disorders

Single gene disorders are those caused by a single mutant allele rather than two. If the mutant allele is recessive, the person usually will not be affected.

However, if the mutant allele is dominant, the mutant copy can override the recessive copy and cause either a less severe form of disease or fully symptomatic disease.

Single gene disorders are relatively rare. The more common heterozygous dominant disorders include:

Huntington’s disease, an inherited disorder that causes brain cells to die. The disease is caused by a dominant mutation in one or both alleles of a gene called huntingtin.

, an inherited disease that leads to the death of brain cells. The disease is caused by a dominant mutation in one or both alleles of a gene called huntingtin. Neurofibromatosis type 1 is an inherited disorder in which nerve tissue tumors develop in the skin, spine, skeleton, eyes and brain. Only one dominant mutation is needed to trigger this effect.

is an inherited disorder in which nerve tissue tumors develop in the skin, spine, skeleton, eyes and brain. Only one dominant mutation is needed to trigger this effect. Familial hypercholesterolemia (FH) is an inherited disorder characterized by high levels of cholesterol, specifically “bad” low-density lipoproteins (LDLs). It is by far the most common of these disorders, affecting about one in 500 people.

A person with a single gene disorder has a 50/50 chance of passing the mutated allele to a child who will become a carrier.

If both parents have a heterozygous recessive mutation, their children have a one in four chance of developing the disorder. The risk is the same for every birth.

If both parents have a heterozygous dominant mutation, their children have a 50 percent chance of getting the dominant allele (partial or complete symptoms), a 25 percent chance of getting both dominant alleles (symptoms), and a 25 percent chance Chance of getting both recessive alleles (no symptoms).

Composite heterozygosity

Composite heterozygosity is the condition in which two different recessive alleles are present at the same locus, which together can cause a disease. These are usually rare conditions, often linked to race or ethnicity.

These conditions include:

Tay-Sachs disease

Tay-Sachs disease is a rare inherited disorder that leads to the destruction of nerve cells in the brain and spinal cord. It is a very variable disorder that can lead to illness in infancy, adolescence or later adulthood.

While Tay-Sachs is caused by genetic mutations in the HEXA gene, it is the specific pairing of the alleles that ultimately determines the form of the disease. Some combinations result in childhood disease, while others result in later-onset disease.

phenylketonuria

Phenylketonuria (PKU) is a genetic disorder that mainly affects children, in which a substance known as phenylalanine builds up in the brain. This leads to seizures, brain disorders and mental retardation. There is a wide variety of genetic mutations associated with PKU, the pairing of which can result in milder or more severe forms of the disease.

Other diseases in which composite heterozygotes may play a role include cystic fibrosis, sickle cell anemia, and hemochromatosis (excessive iron in the blood).

Heterozygous Advantage

While a single copy of a disease allele does not usually result in a disease, there are instances where it can provide protection from other diseases. This is a phenomenon called heterozygous advantage.

In some cases, a single allele can alter a person’s physiological function such that that person becomes resistant to certain infections. Among the examples:

Sickle cell anemia

Sickle cell anemia is a genetic disorder caused by two recessive alleles. The presence of both alleles causes the malformation and rapid self-destruction of the red blood cells. Having only one allele can cause a less severe condition called sickle cell trait, in which only some cells are malformed.

These milder changes are enough to provide a natural defense against malaria by killing the infected blood cells faster than the parasite can reproduce.

cystic fibrosis

Cystic fibrosis (CF) is a recessive genetic disease that can cause severe impairment of the lungs and digestive tract. In individuals with homozygous alleles, CF causes thick, sticky mucus to build up in the lungs and gastrointestinal tract.

In individuals with heterozygous alleles, the same effect, albeit reduced, can reduce a person’s susceptibility to cholera and typhoid. By increasing mucus production, a person is less susceptible to the harmful effects of infectious diarrhea.

The same effect may explain why people with heterozygous alleles for certain autoimmune diseases appear to have a lower risk of later-stage hepatitis C symptoms.

narrative

Dominant refers to a relationship between two versions of a gene. If one is dominant, the other must not be dominant. In this case we call it recessive. A dominant gene, or dominant version of a gene, is a specific variant of a gene that, for various reasons, expresses itself more strongly than any other version of the gene that the person carries and is in this case recessive. Well, it usually refers to patterns of inheritance, often used in conjunction with a Punnett square, where if an individual has two versions of a gene and one is observed to be frequently transmitted from one generation to the other, it is said to be dominant becomes. Biochemically, the point in this case is that genetic variation can, for various reasons, produce either a very beneficial or very detrimental function in a cell that the other version of the gene cannot cover or cancel out or compensate for. In this case, you have a dominant mutation, and that dominant mutation can be benign. It can refer to one eye color or another; this may be a dominant mutation. Or it can refer to an illness. Huntington’s disease, for example, is a dominant mutation where if you carry that version of the HD gene, that mutation, that dominant mutation, gives the individual the disease regardless of what that individual’s other HD gene allele is is. This other allele of the HD gene may be perfectly normal, but the person still has the disease because that one copy of the HD gene is mutated. That’s dominance.

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When a family is diagnosed with a genetic disorder, family members often want to know how likely it is that they or their children will develop the condition. This can be difficult to predict in some cases, as many factors affect a person’s likelihood of developing a genetic condition. An important factor is how the condition is inherited. For example:

Autosomal dominant inheritance: A person affected by an autosomal dominant disorder has a 50 percent chance of passing the altered gene to every child. The probability that a child will not inherit the altered gene is also 50 percent. In some cases, however, an autosomal dominant disease results from a new (de novo) variant that arises during the formation of egg or sperm cells or early in embryonic development. In these cases, the child’s parents are not affected, but the child can pass the disease on to their own children.

Autosomal recessive inheritance: Two unaffected people who each carry one copy of the altered gene for an autosomal recessive disorder (carriers) have a 25 percent chance in each pregnancy of having a child affected by the disorder. The chance of having an unaffected child who is a carrier of the condition in each pregnancy is 50 percent, and the chance of a child not having the condition and not being a carrier is 25 percent. If only one parent carries the altered gene and the other parent does not carry the variant, none of their children will develop the disease, and there is a 50 percent chance of having an unaffected child who is a carrier in each pregnancy.

X-Linked Dominant Inheritance: The likelihood of passing on an X-linked dominant condition differs between males and females because males have one X chromosome and one Y chromosome, while females have two X chromosomes. A man passes his Y chromosome to all his sons and his X chromosome to all his daughters. Therefore, a man with an X-linked dominant disorder will not have his sons affected, but all of his daughters will inherit the disease. A woman passes one or the other of her X chromosomes to each child. Therefore, a woman with an X-linked dominant disorder has a 50 percent chance of having an affected daughter or son in each pregnancy.

X-linked recessive inheritance: Due to the different sex chromosomes, the likelihood of inheriting an X-linked recessive disorder also differs between men and women. A man with an X-linked recessive disorder has his sons unaffected and his daughters carry one copy of the altered gene. In each pregnancy, a woman who carries an altered X-linked recessive gene has a 50 percent chance of having affected sons and a 50 percent chance of having daughters who carry one copy of the altered gene. Women with a gene variant associated with an X-linked recessive disorder typically have no or very mild signs or symptoms of the disorder.

X-Linked: Because the inheritance pattern of many X-linked disorders is not clearly dominant or recessive, some experts suggest that the disorders should be considered X-linked rather than X-linked dominant or X-linked recessive. As mentioned above, the likelihood of passing on an X-linked disorder differs between males and females. The sons of a man with an X-linked disorder are unaffected, but all of his daughters will inherit the altered gene and may develop signs and symptoms of the condition. A woman passes one or the other of her X chromosomes to each child. Therefore, with each pregnancy, a woman with an X-linked disorder has a 50 percent chance of having a child with the altered gene. An affected daughter may have milder signs and symptoms than an affected son.

Y-Linked Inheritance: Because only males have a Y chromosome, only males can be affected by and pass on Y-linked disorders. All sons of a man with a Y-linked disorder will inherit the condition from their father.

Codominant Inheritance: In codominant inheritance, each parent contributes a different version of a particular gene, and both versions affect the resulting genetic trait. The chance of developing a genetic condition with codominant inheritance and the characteristic features of this condition depend on which versions of the gene are passed from parents to their child.

Mitochondrial Inheritance: Mitochondria, the energy-producing centers in cells, each contain a small amount of DNA. Diseases with mitochondrial inheritance result from variants in mitochondrial DNA. Although these disorders can affect both men and women, only women can pass mitochondrial DNA variants to their children. A woman with a disorder caused by changes in mitochondrial DNA will pass the variants on to all her daughters and sons, but the children of a man with such a disorder will not inherit the variant.

It is important to note that the possibility of passing on a genetic condition applies equally to any pregnancy. For example, if a couple has a child with an autosomal recessive disorder, the chance of having another child with the disorder is still 25 percent (or 1 in 4). Having a child with a disorder does not protect future children from inheriting the condition. Conversely, having a child without the condition does not mean that future children will definitely be affected.

Although the odds of inheriting a genetic condition seem simple, factors such as a person’s family history and genetic testing results can sometimes alter those odds. Additionally, some people with a disease-causing variant never develop health problems or may only have mild symptoms of the disorder. When a disease that runs in a family does not have a clear inheritance pattern, it can be particularly difficult to predict a person’s likelihood of developing the disease.

Assessing the likelihood of developing or passing on a genetic disorder can be complex. Genetics experts can help people understand these opportunities and help them make informed decisions about their health.

Find the first column in the square. (See the red dashed line in Figure 4.1) Write the first allele of the maternal genotype in each of the two boxes in this column. Repeat steps one and two for the second column. However, use the second allele from the mother’s genotype in the boxes. Find the first row in the square. (See the blue solid line in Figure 4.1) Write the first allele of the father’s genotype in each of the two boxes in this row. Repeat steps four and five for the second row. However, use the second allele from the father’s genotype in the boxes. Each box should contain two letters at the end. These two letters form the genotype for an offspring. (See Figure 4.2)

a. Note: This process represents that each parent passes on alleles and thus traits to their offspring.

b. Note: Additional colors are not required, they are only used to clarify where each allele comes from

explanation

We know that the yellow dog must be homozygous recessive and the brown dog must be either heterozygous or homozygous dominant. If B is used to represent the dominant brown allele and b is used to represent the recessive yellow allele, this means that the yellow parent must be bb and the brown parent can be either BB or Bb.

We know that all puppies must carry a dominant allele as they all have the dominant phenotype. The yellow parent carries only the recessive allele. This indicates that each pup must have inherited a dominant allele from the brown parent. The most likely genotype from the brown parent would be homozygous dominant, resulting in all puppies being heterozygous and brown.

bb x bb

All offspring will be Bb and will express the dominant brown phenotype.

Note, however, that we cannot determine the genotype of the brown parent with certainty. Because of the independent sorting, it is possible that a heterozygous brown parent happened to have passed the recessive allele to all offspring.

B x bb

Half of the offspring will be Bb and the other half will be bb.

The probability of producing six brown puppies from this cross would be equal to half to the sixth power or 1.56%. While this is a very small chance, it is not impossible and we cannot rule out a heterozygous genotype for the brown dog.