What Is The Genotype For Brown Eyes?

What Is The Genotype For Brown Eyes
Genotypes In one sense, the term ” genotype “—like the term “genome”—refers to the entire set of genes in the cells of an organism. In a narrower sense, however, it can refer to different alleles, or variant forms of a gene, for particular traits, or characteristics. An organism’s genotype is in contrast with its phenotype, which is the individual’s observable characteristics, resulting from interactions between the genotype and the environment. There is a complex connection between the genotype and the phenotype. Since the phenotype is the result of an interaction between genes and the environment, different environments can lead to different traits in individuals with a particular genotype. In addition, different genotypes can lead to the same phenotype. This happens because genes have different alleles. For some genes and traits, certain alleles are dominant while others are recessive, A dominant trait is one that shows up in an individual, even if the individual has only one allele”>allele that produces the trait. Some aspects of eye color work this way. Brown eyes, for instance, are dominant over blue eyes. This is because a pigment called melanin produces the brown color, while having no pigment leads to blue eyes. Having just one allele for the dark pigment is enough to make your eyes brown. There actually are several different pigments that affect eye color, each pigment resulting from a particular gene. This is the reason why people can have green eyes, hazel eyes, or any of a range of eye colors apart from blue or brown. When discussing genotype, biologists use uppercase letters to stand for dominant alleles and lowercase letters to stand for recessive alleles. With eye color, for instance, “B” stands for a brown allele and “b” stands for a blue allele. An organism with two dominant alleles for a trait is said to have a homozygous dominant genotype. Using the eye color example, this genotype is written BB. An organism with one dominant allele and one recessive allele is said to have a heterozygous genotype. In our example, this genotype is written Bb. Finally, the genotype of an organism with two recessive alleles is called homozygous recessive. In the eye color example, this genotype is written bb. Of these three genotypes, only bb, the homozygous recessive genotype, will produce a phenotype of blue eyes. The heterozygous genotype and the homozygous dominant genotype both will produce brown eyes, though only the heterozygous genotype can pass on the gene for blue eyes. The homozygous dominant, homozygous recessive, and heterozygous genotypes only account for some genes and some traits. Most traits actually are more complex, because many genes have more than two alleles, and many alleles interact in complex ways. : Genotypes

Is brown eyes a genotype or phenotype?

Phenotype – Generally speaking, a phenotype is an inherited characteristic that we perceive. Eye color, hair color, and blood type are all phenotypes. You may have a brown-eye phenotype, and your eyes will, therefore, be brown; a brown-hair phenotype and your hair will be brown, or an A blood type phenotype and your blood type will be A.

Why does BB genotype result in brown eyes?

Combinations – Let’s take this back to science class. As mentioned earlier, every human has two copies of genes, deriving from both the mother and father. When two copies are dominant it’s called homozygous, which we can label as “BB”. Conversely, when two copies are recessive, it’s labeled as “bb”, or heterozygous.

When finding out what eye colors are dominant between you and your partner, it’s important to keep in mind the fact that combinations of these genes exist and could affect your child’s eye color. For example, when someone has brown eyes, it doesn’t necessarily mean they have homozygous genes. It’s possible for them to have a combination, or “Bb”, having one dominant brown allele and one recessive blue allele.

In this case, because brown is dominant over blue, they will have brown eyes. Below is a chart that shows an example of how you could determine your child’s eye color, given you know exactly what gene combination the mother and father possess. In this example, we will say the mother has brown eyes, but carries a recessive blue allele from her father.

The father in this example has blue eyes and carries both recessive alleles. The white boxes indicate the combinations of these alleles that your child could have. As you can see in this example, your child has a 50/50 chance of getting brown (Bb) or blue eyes (bb). If the mother had a dominant homozygous genotype (BB), all of your child’s combinations would read “Bb”, meaning they would likely have brown eyes.

Things start to get a little complicated if you don’t know exactly what eye colors are dominant in your family lineage, but most of the time you can determine the probability pretty easily by understanding the dominance order: Brown, followed by green, and, last but not least, recessive blue.

What is the phenotype for brown eyes?

Introduction – Eye colour, or more correctly iris colour, is often used as an example for teaching Mendelian genetics, with brown being dominant and blue being recessive. Colour blindness “Daltonism”, which affects 8% of the male population, is a leading example for teaching X-linked recessive disease (Fig.1 ).

  • This simple model works well most of the time, with the main blue eye gene OCA2,
  • We can draw pedigrees showing homozygote blue- and homozygote brown-eyed parents having heterozygote brown-eyed children and then grandchildren who may be homozygote or hererozygote blue- or brown-eyed depending on their other parent (Fig.2 ).

Fig.1: Basic Mendelian Genetics of Eye Colour and Colour Perception. What Is The Genotype For Brown Eyes Upper row: Brown, Hazel/Green, Blue and Albino eyes as seen by most of the tritanopic “normal” population. Lower row: the same eyes as would be perceived by a person with X-linked protanopia. Fig.2: Simple four-generation Mendelian Pedigree of Brown and Blue eyes. What Is The Genotype For Brown Eyes Phenotype shown as brown or blue while dominant brown gene = B and recessive blue gene = b Individuals with bb have blue eyes, while individuals with BB or Bb have brown eyes. Blue or brown describes only a portion of eye colour. There are intermediate variations of green and hazel, as well as albino eyes, which lack pigment entirely—all examples for which the simple Mendelian model does not apply.

Geneticist Victor McKusick stated, “The early view that blue is a simple recessive has been repeatedly shown to be wrong by observation of brown-eyed offspring of two blue-eyed parents”, This may have inspired his own interest in genetics, as he and his identical twin brother had brown eyes and their parents had blue! We now know that eye colour is actually a complex genetic trait, involving interaction of some major genes and many minor genes.

This Mendelian-Complex genetic explanation for eye colour also crosses over into the genetics of many other eye diseases such as age-related macular degeneration and glaucoma. Many people can look at the eye colours in their own families and draw their own pedigrees to see how the Mendelian model applies.

Individuals of Asian or African ancestry, most of whom have brown eyes, can still look at other families. Capturing the attention of the public with eye colour and genealogies was done marvellously by the TV series (and books) of Game of Thrones. Viewers tried to predict events based on eye colour, “I see a darkness in you.

And in that darkness, eyes staring back at me. Brown eyes, blue eyes, green eyes. Eyes you’ll shut forever. We will meet again.” Melisandre. Game of Thrones season 3.

What is the genotype for heterozygous brown eyes?

– Alleles for the same trait must be in separate sex cells. individuals. – Father has Brown eyes and is heterozygous (Bb). – Mother has Brown eyes and is heterozygous (Bb).

What are the 3 types of genotypes?

Difference between Genotype and Phenotype – Following are the important difference between genotype and phenotype.

Genotype Phenotype
The hereditary information of the organism is in the form of genes in the DNA and remains the same throughout the life. The characteristics of an organism which are visible are known as phenotypes.
The same genotype produces the same phenotype. The same phenotype may or may not belong to the same genotype.
Present inside the body as genetic material. Expression of genes as the external appearance.
The genotype is inherited from the parent to the offspring. The phenotype is not inherited from the parent.
It can be determined by scientific methods such as the polymerase chain reaction. It can be determined by observing the organism.
It is affected by genes. It is affected by genotype and environmental conditions.
For e.g., Blood group, eye colour, height, and genetic diseases. For e.g., Weight, physique, and beak of birds

Also Read : For more information on the difference between genotype and phenotype, keep visiting BYJU’S website or download BYJU’S app for further reference. The set of genes in our DNA responsible for a particular trait is known as a genotype. The chemical composition of the DNA gives rise to the phenotype.

Organisms with even a slight gene difference are said to have different genotypes. The physical characteristics of an organism which are the outcome of the interaction of the genotype with the environment, are known as the phenotype. It depends upon the genes which are dominant. Shape. size, colour, the behaviour is the phenotype of an organism.

The different types of genotypes are- homozygous recessive (pp), homozygous dominant (PP), and heterozygous (Pp). The homozygous dominant and the heterozygous genotypes show the same phenotypes. Alleles are the variants of genes, whereas the set of genes responsible for certain traits are known as genotypes.

  • However, both determine biological traits, but the copies might not be the same.
  • Genotype and phenotype are two different concepts but are closely related to each other.
  • Phenotype refers to the physical traits that are observed in an organism which are the outcome of the expression of the genes of an individual.

The genotype determines the phenotype of an individual. Genotypes can be homozygous or heterozygous. Heterozygous genotypes express dominant traits. A recessive trait is expressed if the genotype has two recessive alleles. The genotype of an individual is influenced by environmental factors in which the organism lives or the internal body environment of an organism, such as hormones and metabolism. Put your understanding of this concept to test by answering a few MCQs. Click ‘Start Quiz’ to begin! Select the correct answer and click on the “Finish” buttonCheck your score and answers at the end of the quiz Visit BYJU’S for all Biology related queries and study materials

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View Quiz Answers and Analysis : Difference Between Genotype And Phenotype

What is my genotype?

14:26 1st September 2017 | Genotype Genotype SS AA AS AC Sickle Cells Heamoglobin Genotype Tests Genetic Constitution Blood Type Type A Type B Type AB Type O Blood Group Compatibility HB Electrophoresis Blood Disorder ABO/RH BloodtypeIn this blog post we will look at the definition of the words genotype and blood group and why it is important to know your genotype and your blood group compatibility.

We will also look at the tests used to determine genotype and blood types and which tests are offered by Bridge Clinic. What is a Genotype? A genotype is the entire genetic constitution of an individual, i.e. the genetic makeup of an organism or group of organisms with reference to a single trait, set of traits, or an entire complex of traits.

In a nutshell: your genotype is your complete heritable genetic identity; the sum total of genes transmitted from parent to offspring. There are four hemoglobin genotypes (hemoglobin pairs/formations) in humans: AA, AS, SS and AC (uncommon). SS and AC are the abnormal genotypes or the sickle cells,

We all have a specific pair of these hemoglobin in our blood which we inherited from both parents. Why it’s Important to Know Your Genotype Knowing one’s hemoglobin genotype before choosing a life partner is important because there may be compatibility issues which could have devastating effects when it comes to conception.

Individuals with sickle cells experience severe pains in body parts where oxygen flow is compromised due to blockage in the blood vessels. Read about sickle cell disease here,

AA can marry anybody AS is better off with AA AS and AS, AS and AC are too risky Two sickle cells = avoid conception

Types of Hemoglobin Genotype Tests Newborn Screening | Diagnostic Testing | Carrier Testing | Prenatal Testing | Preimplantation Testing | Predictive and Presymptomatic Testing | Forensic testing What is a Blood Group and Type? To classify blood, antibodies and inherited antigenic substances on the surface are evaluated. There are four blood GROUPS:

Type A (marker A) Type B (marker B) Type AB (blood cells have both A and B markers) Type O (blood cells have neither A or B markers)

An Additional Marker in Blood: Rhesus factor This is simply a protein that may be present on the surface of red blood cells. Some people have it and others don’t. If you have it, your blood type is further classified as positive ; if you don’t, your blood type is further classified as negative,

O- No A or B Marker O+ No A or B Marker + Rhesus factor (One of the Two Most Common Types) A- A Marker Only A+ A Marker but No B Marker + Rhesus factor (One of the Two Most Common Types) B- B Marker Only B+ B Marker but No A maker + Rhesus factor AB- A and B Markers Only AB+ All 3 Types of Markers: A, B and Rhesus factor

Why it’s Important to Know Your Blood Group Compatibility It is important to know your blood type if you need a blood transfusion or if you want to donate blood. It also plays a role in determining paternity. Before a blood transfusion takes place it must be established that the donor’s blood type is compatible with the recipient’s blood type.

  • The combination of certain antibodies (proteins protecting the body) can be harmful or even lead to fatal symptoms if antibodies perceive foreign cells as a threat.
  • It is our immune systems’ way of protecting us.
  • Types of Blood Test Complete Blood Count (CBC) | Blood Chemistry Tests | Blood Enzyme Tests | Blood Tests to Assess Heart Disease Risk.

Tests Offered by Bridge Clinic 1. HB ELECTROPHORESIS: Hemoglobin Electrophoresis Test (Code: HELEC P) Hemoglobin is a protein that transports oxygen. Hemoglobin abnormalities, caused by genetic mutations, can result in certain diseases or disorders. This test is therefore used to detect abnormal forms and/or relative amounts of hemoglobin.

See also:  Why Is It Blue Under My Eyes?

Diagnose a blood disorder if symptoms suggest it Routine checkup as part of a blood test during a physical Screen for genetic conditions, e.g. sickle cell anemia, before conceiving. Monitor existing conditions

Bridge Clinic as also offers PGD and PGS, Preimplantation genetic diagnosis (PGD) can be performed during i n vitro fertilisation (IVF) to choose embryos without certain diseases/conditions. Additionally, some chromosomal abnormalities can be picked up during a preimplantation genetic screening (PGS).2.

Ensure the right blood type is used for transfusions Check if two people could be blood relatives Check a pregnant woman’s blood type

Get in touch to book a test or to find out more about your genotype and blood type. Email [email protected] | Call 01 631 0092 / +234 (0)1 631 0092 Book Your Appointment Today

What color eyes is BB?

Why are our kids’ eyes different colours? – Let’s look at why a blue-eyed parent (dad) and a brown-eyed parent (mum) and can have brown, green, and blue-eyed children. For gene 1, OCA2, there are two possibilities: brown or blue. The brown version of gene 1 is dominant over the blue one. Dominant means that if at least 1 of your two copies is brown (Bb), then you will have brown eyes. Geneticists represent the different versions of the eye colour gene as B for brown and b for blue (the capital letter is the dominant, the lowercase, recessive).

So brown eyes are either Bb or BB and blue eyes are bb. For gene 2, there are two possibilities, green or blue. Green is dominant over blue. Green eyes can be GG, or Gb, while blue eyes are bb. Brown is dominant over green, so if you have a B version of gene 1 and a G version of gene 2, you will have brown eyes.

The possible gene combinations that can give you brown, green, or blue eyes are shown in the chart. Back to the green or blue-eyed children. Dad can only be bb bb as he has blue eyes. Since mum has brown eyes, she could have any of six different possibilities.

Is brown eyes a dominant gene?

Eye color inheritance pattern – Due to the number of genes involved in eye color, the inheritance pattern is complex. Although a child’s eye color can generally be predicted by looking at the color of the parents’ eyes, the polymorphisms that can arise mean a child may well have an unexpected eye color.

  1. A child’s eye color depends on the pairing of genes passed on from each parent, which is thought to involve at least three gene pairs.
  2. The two main gene pairs geneticists have focused on are EYCL1 (also called the gey gene) and EYCL3 (also called the bey2 gene).
  3. The different variants of genes are referred to as alleles.

The gey gene has one allele that gives rise to green eyes and one allele that gives rise to blue eyes. The bey2 gene has one allele for brown eyes and one for blue eyes. The allele for brown eyes is the most dominant allele and is always dominant over the other two alleles and the allele for green eyes is always dominant over the allele for blue eyes, which is always recessive.

  • This means parents who happen to have the same eye color can still produce a different eye color in their child.
  • For example, if two parents with brown eyes each passed on a pair of blue alleles to their offspring, then the child would be born with blue eyes.
  • However, if one of the parents passed on a green allele, then the child would have green eyes and if a brown allele was present, then the child would have brown eyes irrespective of what the other three alleles were.

Chromosome 15 – Eye colour However, this does not explain why two parents with blue eyes can have a child with brown eyes. It also does not explain how grey or hazel eyes arise. This is where modifier genes, other genes associated with eye color and mutations all come into picture, as they can all lead to variability in eye color.

Is BB and BB the same genotype?

Genotype – The genotype is the genetic combination of two alleles. If, for example, a child has received one brown-eye allele – represented by ‘B’ – and one blue-eye allele – represented by ‘b’ – then their genotype would be ‘Bb’. If, however, the child received two brown-eye alleles their genotype would be ‘BB’; and a child with two blue-eye alleles ‘bb’.

What is the genotype for eye color?

Hect domain and RCC1-like domain-containing protein 2 (HERC2) and OCA2 – Finally, two major genes are responsible for eye color: HERC2 and OCA2. During the first studies to classify genes for eye color, OCA2 was believed to be the dominating factor for eye color determination.3, 6, 7, 8 Within the last couple of years, HERC2, an ubiquitin ligase-coding region, has been linked more strongly to eye color.

  1. Both genes are located on chromosome 15.
  2. OCA2 ranges from 15q11.2-12 and HERC 2 starts at 15q13.
  3. These genes are of the greatest importance for eye color.9, 10, 11 Numerous ubiquitin ligases are coded for throughout the body.
  4. Chromosome 15 contains HERC1 and HERC2.
  5. Problems with just HERC2 lead to nerve tissue malfunctioning, small size and semi-sterility or sterility.

They help with hormone secretion, which affects the pituitary and can lead to dysfunction of the hypothalamus and other protein complexes. The large HERC2 gene requires 211 kb and 93 exons that codes for a 528 kDa protein made of 4834 residues.12 OCA2 codes for a major transmembrane protein in the melanosome maturation process: P protein.

Similar to membrane-associated transporter protein, it transports melanosomes, but additionally, it controls their pH.3, 13 Therefore, the P protein encoded by OCA2 affects the amount and quality of melanin that deposits in melanocytes. In mice and humans where the P protein is nonfunctional, albinism occurs, indicating its crucial role in pigmentation.13, 14 The gene located 11.7 kb from HERC2 requires 345 kb, but it requires only 24 exons to produce a 110 kDa protein with 838 residues.

These two seemingly unrelated genes have a major effect on eye color in humans.

What is the genotype of the brown parent?

Understanding Punnett Squares and Test Crosses – AP Biology A breed of dog can be either of two colors. In this breed, brown is dominant to yellow. A brown dog mates with a yellow dog and produces a litter of six brown dogs. What is the genotype of the parental brown dog? Possible Answers: Unable to determine from the given information Correct answer: Unable to determine from the given information Explanation : We know that the yellow dog must be homozygous recessive and that the brown dog must be either heterozygous or homozygous dominant.

  1. 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 could be either BB or Bb,
  2. We know that all of the puppies must carry a dominant allele, since they all express the dominant phenotype.

The yellow parent only carries the recessive allele. This indicates that every puppy must have inherited a dominant allele from the brown parent. The most likely genotype of the brown parent would be homozygous dominant, which would lead to all puppies being heterozygous and brown.

  1. BB x bb All offspring will be Bb and express the dominant brown phenotype.
  2. Note, however, that we cannot determine the genotype of the brown parent for certain.
  3. Due to independent assortment, it is possible that a heterozygous brown parent gave the recessive allele to all offspring by chance.
  4. Bb x bb Half offspring will be Bb and half will be bb,

The probability of getting six brown puppies from this cross would be equal to one-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. In a species of lizard, green coloration is dominant to blue coloration.

  1. A breeder wants to produce as many blue lizards as possible from one cross.
  2. Which of the following crosses will produce the highest percentage of blue lizards? Possible Answers: Explanation : The question tells us that green is dominant to blue.
  3. This means that the C allele must correspond to green and the c allele must correspond to blue.

We are looking for the cross that will produce the most blue offspring. Since blue is recessive, all blue offspring will be homozygous recessive; thus, we are essentially looking for the cross that carries the most recessive alleles. Of the given crosses, cc x cc contains the greatest number of recessive alleles. Correct answer: Explanation : Heterozygous organisms carry one dominant allele and one recessive allele. The dominant allele is expressed over the recessive allele, giving the organism the dominant phenotype. If the heterozygous rat in the question is brown, then we can conclude that brown is dominant to white.

  • The cross of these two rats would be:
  • Parents: BB (brown) x Bb (brown)
  • Offspring: half BB (brown), half Bb (brown)

Though half of the offspring will be homozygous and half will be heterozygous, all offspring will be brown. None of the offspring from this cross will show the white phenotype. If a male is heterozygous for the dimples allele and marries a female who does not possess the allele needed for dimples, what is the chance their child will have dimples? Dimples are an autosomal dominant trait.

  1. Possible Answers: Explanation : By creating a Punnett square in which the male carries the label Dd and the female has the label dd, one can see the possible combinations of alleles that the child may have.
  2. D will symbolize the allele for dimples, and d will symbolize the allele for no dimples.
  3. The cross will be Dd x dd,

There is a 50% chance that the child does not obtain the allele needed for dimples ( dd ), and a 50% chance that the child is heterozygous ( Dd ). Because dimples is an autosomal dominant trait, heterozygosity will express dimples, leading to a 50% chance that the child will have dimples.

  1. A new species of insect was recently discovered.
  2. Scientists have found that orange coloration is recessive to yellow coloration.
  3. If a heterozygous yellow insect is mated to an orange insect, what are the expected phenotypic percentages of the offspring? Possible Answers: Correct answer: 50% yellow, 50% orange Explanation : We are told that the yellow parent is heterozygous, so we can set up a simple cross.

We know that the orange insect must be homozygous recessive due to the fact that it displays the orange phenotype. In our cross, we will use A as the dominant allele and a as the recessive allele. This gives the yellow parent a genotype of Aa and the orange parent a genotype of aa,

  1. Aa x aa Possible offspring: Aa, Aa, aa, aa We can see that there are only two possible genotypic results.
  2. Half of the offspring will be Aa and half will be aa,
  3. The Aa offspring will be yellow and the aa offspring will be orange, giving a 1:1 phenotypic ratio.
  4. In pea plants, tall is dominant for height, green is dominant for color and round is dominant for pea shape.

A tall green plant is crossed with a short yellow plant.50% of the offspring are tall and green, and 50% are tall and yellow. What are the genotypes of the parent plants? Possible Answers: Tall-green: ttgg Short-yellow: TTGg Tall-green: TTGg Short-yellow: ttgg Tall-green: TtGg Short-yellow: ttgg Tall-green: TtGG Short-yellow: ttgg Tall-green: TTGG Short-yellow: ttgg Correct answer: Tall-green: TTGg Short-yellow: ttgg Explanation : Let’s look at each trait individually.

  1. We can see that all of the offspring from this cross will be tall; the tall allele must be dominant over the recessive allele.
  2. We also know that one parent must be homozygous dominant for the tall allele, since it is passed to every single offspring.
  3. The parent genotypes for height are TT (tall) and tt (short).

The short plant must be homozygous recessive to show the recessive phenotype. Now, let’s look at color. Half of the offspring are green and half are yellow. This tells us that whichever parent displays the dominant phenotype is also heterozygous, allowing the recessive phenotype to appear in the offspring.

Since we know that green is dominant, we know that the green plant must be heterozygous. In order to display the recessive yellow phenotype, the yellow plant must be homozygous recessive. The parent genotypes for color must be Gg (green) and gg (yellow). Together, we can see that the tall-green plant will be TTGg and the short-yellow plant will be ttgg,

A biologist genetically crosses two cats, both with black fur, which is dominant over white fur. The pair have 12 kittens, 9 with black fur and 3 with white fur. What is the parental cross? Possible Answers: Explanation : The ratio of kittens with black fur to kittens to white fur is 3:1.

  1. Since the recessive phenotype is shown in the offspring, we know that both of the parents are carriers of the recessive genotype and are thus both heterozygous, Bb.
  2. Assume that in the organism in question, the allele for brown fur ( B ) is dominant to the allele for white fur ( b ).
  3. Also assume that the allele for curly fur ( C ) is dominant to the allele for straight fur ( c ).

Finally, assume these genes are independent. Given parents with the genotypes BBCc and Bbcc, what fraction of offspring will display straight, brown fur? Possible Answers: Correct answer: Explanation : Each parent will contribute one allele at random from each of the two genes. The odds of having brown fur, given the parental genotypes, is 100% because all children will receive a dominant allele for brown fur ( B ) from the first parent.

  • This means that the odds of having brown straight fur will depend only on the odds of having straight fur.
  • Having straight fur requires one recessive allele ( c ) from each parent.
  • The second parent will always contribute a recessive allele while the first will contribute a recessive allele half the time.

Thus, the odds of straight fur is 50%, as are the odds of straight, brown fur. Alternatively, a Punnett square may be used. The square below shows the 50% offspring combinations with straight, brown fur highlighted in red. If two parents are heterozygous for a trait and they have children, what is the percentage of the children that are heterozygous for the trait? Possible Answers: Explanation : For simplicity, we will assign the letter ” a ” for the gene of interest.

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Thus, the heterozygous genotype is Aa. You may sketch a punnet square of the cross: Aa x Aa to help illustrate that the combinations result in 50% chance of heterozygous offspring. In a cross in which both parents are heterozygous, what would be the percentage of offspring that are homozygous recessive for the trait? Possible Answers: Explanation : Arbitrarily, we may assign the letter ” b ” for the gene of interest.

The cross then is as follows: Bb x Bb. Each parent has a 50% chance of donating a recessive ( b ) allele to the offspring. We must multiply these probabilities to get the chance of a homozygous recessive offspring. Cheyenne Certified Tutor University of South Florida-Main Campus, Bachelor of Science, Biomedical Sciences.

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What is the recessive of brown eyes?

The Single Gene Trait – There is one genetic variation, a human trait that has a single gene governing it, and that is eye color which is blue or brown. Brown eyes are dominant and blue eyes recessive. Following the logic of yellow and green peas and making a Punnett square, it should be impossible for two blue-eyed parents to have a brown-eyed child but it would be possible for brown-eyed parents to have a blue-eyed child if both parents were a genetic mixture of one blue-eye and one brown-eye gene.

  1. In the single-gene paradigm, two blue-eyed parents have only blue-eye genes and can, therefore, produce only blue-eyed children.
  2. However, eyes are not just blue or brown but some people in the Asian population have eyes so dark that look almost black.
  3. There are blue-eyed Scandinavians, and groups with gray, green, violet, hazel, and a myriad of colors.

Learn more about the human characteristics that aren’t governed by a single gene,

Is AA a genotype or phenotype?

Determining how humans inherit ABO blood groups Learn how humans can inherit the A, B, and O blood types In ABO blood groups, a person’s blood type is determined by two genes, one inherited. Encyclopædia Britannica, Inc. A, B, and O blood groups are determined by different types of antigens on red blood cells.and the antigens on red blood cells are determined by specific genes in the body.

There are three alternate forms of the gene that codes for these antigens: A codes for the A antigen B codes for the B antigen And O codes for no antigen. Even though there are three possible alleles for blood type, only two appear at the locus for the trait. And unlike some other genes, A, B, and O are codominant.

This means that both genes are expressed at the same time. Therefore, your blood type depends on not one, but two genesone inherited from each parent. If you have an AA or AO genotype, you will have the phenotype of type A blood; if you have a BB or BO genotype, you will have a type B blood phenotype; if you have an AB genotype, you will have a type AB blood phenotype; and if you have an OO genotype, you will have a type O blood phenotype.

Let’s use a Punnett square to find the probability of a person inheriting a particular blood type Let’s say a person’s parents have genotypes of AO and AB. The AO parent can contribute an A or an O gene. The AB parent can contribute an A or a B gene. Working the Punnett square results in a 25% probability of each of the following genotypes: AA, AO, AB, and BO.

Okay, but what about the phenotypes? Remember, in the ABO blood groups, the phenotype is the blood type of the person. Here, a child born of these parents has a 50% chance of inheriting the type A phenotype, or blood type. The chance he or she will have type AB blood is 25%, and the chance of type B blood is 25%.

What is aa heterozygous genotype?

(HEH-teh-roh-ZY-gus JEE-noh-tipe) The presence of two different alleles at a particular gene locus. A heterozygous genotype may include one normal allele and one mutated allele or two different mutated alleles (compound heterozygote).

What is genotype AA?

“Your child is SS!” This is the last thing any parent wants to hear but it’s quite a common situation that results from a lack of knowledge and assumptions we make about our genotype because of thoughts like “my Father is AA so I must be AA and my child will be AA as well.” These guess games are unnecessary when you can simply get tested to know what you and your spouse’s blood group and genotype are.

“So before your I do, do you know your blood group and genotype? Are you compatible with your spouse?” A blood group (also known as a blood type) is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells (RBCs).

There are four major blood groups determined by the presence or absence of A and B antigens on the surface of red blood cells. In addition to the A and B antigens, there is a protein called the Rhesus factor (Rh factor), which can either be present (+) or absent (–), creating the 8 most common blood types;


Blood group compatibility becomes a concern for couples if a pregnancy is involved. This is because of the Rh factor. When the woman is Rh- and the baby is RH+, blood cells from an Rh+ baby coming in contact with its Rh- mother’s bloodstream during pregnancy, labour, and delivery, might set off an immune response producing antibodies.


AC genotype is abnormal haemoglobin produced because of the substitution of protein substitution in the gene of the red blood cell. People with haemoglobin AC traits are normal and do not show signs of any disease. SC genotype refers to another abnormal genotype of haemoglobin that causes recurrent anaemia.

The C allele is also a mutant allele type, producing abnormal haemoglobin called haemoglobin C. SC genotype is called sickle cell-haemoglobin C. However, not everyone will present with recurrent anemia. The CC genotype is often referred to as homozygous normal. Some people born with CC will have Hemoglobin C disease.

This disease may produce mild to moderate anemia, jaundice, enlarged spleen and gallstones, while others might not present with any disease. Two people are said to have compatible genotypes when there is no possibility of them birthing a child with sickle cell disease.

AA + AA = compatibleAA + AS = compatibleAA + SS = compatibleAA + AC = compatible AS + AS = incompatibleAS + AC = incompatibleAS + SS = incompatibleAS + SC = incompatibleSS + SS = IncompatibleAC + SS = incompatibleSC + SS = incompatible

These two are often confused but they are different. Blood group shows the types of antibodies and antigens found on red blood cells as in A, B, AB or O. Blood genotype shows the type of haemoglobin present in blood cells. Your blood genotype will show whether you have normal, career or sickled red blood cells.

Tests are required to ascertain what your blood group and blood genotype is. There are different types of genotype testing. Qualitative tests – These tests can not always be relied on hence confirmatory quantitative tests might be required, as they can’t detect quite a number of abnormal haemoglobin variants and Thalassemia.

Quantitative tests – This test is ideal, with the preferred being haemoglobin quantification by capillary zone electrophoresis or HPLC. Quantitative methods give more detailed results and show a wider spectrum of haemoglobin abnormalities including Thalassemia and other less common haemoglobin variants like Haemoglobin C and D etc.

What is A+ in genotype?

If someone has blood type A+: which are his possible genotypes and who can he donate blood to? The ABO blood type system relies upon the co-dominant alleles I A and I B, which are expressed any time they are present and are dominant over i which is recessive.

If someone has blood type A, that means in their genotype they have at least one I A allele, for otherwise they would not express phenotype A. In addition we can infer, they do not have allele I B in their genotype, because if they had it, they would express it. So the possible genotypes of someone whose phenotype is A+ are: I A I A (homozygote: both alleles are the same) and I A i (heterozygote: alleles are different).

In both cases, A would be expressed and B would not, so the phenotype would be A. Regarding the +/- blood type, this trait is determined by the presence of the allele Rh which is dominant over rh (which is recessive). Whenever Rh is present, it is expressed and the phenotype is +.

  1. Since for the studied individual the phenotype is +, we know Rh is present.
  2. But we do not know if the individual is heterozygote or homozygote: so there are two possible genotypes RhRh and Rhrh.
  3. Regarding blood donation, the key idea to consider is that one can only donate to people that have the same antigens (traits like +, A or B) than one has.

This includes people who have the same antigens plus some extra ones. The reason for this is that the body only rejects antigens that are foreign to theirs. An individual with phenotype A+ has got antigens A and +. So he cannot donate to people who do not have antigens A and +: that rules out A- (they do not have +), B- (they do not have A or +), AB- (they do not have +), 0- (they do not have A or +), 0+ (they do not have A) and B+ (they do not have A).

Is genotype AA the best?

What Blood Genotypes Are Compatible? – The AA genotype has the best compatibility ratio. An individual with the AA genotype can choose a life partner from virtually all other genotype categories with an extremely minimal possibility of sickle-celled offspring.

  1. Some research also shows that while the AA genotype is the best in terms of compatibility, it is also the most susceptible to malaria.
  2. So if you have the AA blood genotype, it is advisable that you minimize your exposure to mosquitoes and take other malaria prevention strategies seriously.
  3. The AS genotype is best compatible with the AA.

A genotypic pairing of AS with AS or AS with AC poses an increased chance of sickle-celled offspring. Similarly, a pairing between AS and SS or the AC and SS is equally as risky and ill-advised, while a pairing of two sickle-celled individuals will almost certainly result in sickle-celled offspring.

  • 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)

What is the genotype of a girl?

Roughly speaking, sex can be considered in terms of three categories: genotypic sex, phenotypic sex, and gender. Genotypic sex refers specifically to an individual’s two sex chromosomes. Most people have either two X chromosomes (genotypic female) or an X and a Y chromosome (genotypic male).

  • Phenotypic sex refers to an individual’s sex as determined by their internal and external genitalia, expression of secondary sex characteristics, and behavior.
  • If everything proceeds according to plan during development ( Box A ), the XX genotype leads to a person with ovaries, oviducts, uterus, cervix, clitoris, labia, and vagina—i.e., a phenotypic female.

By the same token, the XY genotype leads to a person with testicles, epididymis, vas deferens, seminal vesicles, penis, and scrotum—a phenotypic male. Gender refers more broadly to an individual’s subjective perception of their sex and their sexual orientation, and is therefore harder to define than genotypic or phenotypic sex.

What genotype can AA marry?

Genotype can be simply defined as the genetic constitution of an individual organism. This is different from your phenotype which is a description of your actual physical characteristics. It is imperative to know your genotype before you say “yes” to that handsome guy or to that beautiful lady whom you wish to spend the rest of your life with or if you are in a relationship in which there are chances of conception.

See also:  When I See Those Pretty Green Eyes?

The problem to avoid with genotype compatibility for intending couples is the sickle cell disease (a recessive disorder)-a very serious medical condition with high prevalence rates in Africa south of the Sahara. Types of Genotype The genotypes in humans are AA, AS, AC, SS. They refer to the hemoglobin gene constituents on the red blood cells.

AC is rare whereas 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, (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) Compatible genotypes for marriage are: AA marries an AA. That’s the best compatible. That way you save your future children the worry about genotype compatibility.

AA marries an AS. You’ll end up with kids with AA and AS which is good. But sometimes if you’re not lucky all the kids will be AS which limits their choice of partner. AS and AS should not marry, there is every chance of having a child with SS. AS and SS shouldn’t think of marrying.

  1. And definitely, SS and SS must not marry since there’s absolutely no chance of escaping having a child with the sickle cell disease.
  2. Solution The only thing that can change the genotype is the bone marrow transplant (BMT).
  3. It has been proven to be the only promising permanent cure to SS, SC, and CC; however, it is new, very expensive and cannot be done in any part of Africa.

It also carries some risks. Health tips are supplied by the AUN Health Center

How do I know my blood genotype?

ABO Blood Groups: Predicting the Blood Type of Your Children – Introduction The Human Genetics Tutorial with problem solving exercises concerning the inheritance of the ABO blood group alleles has resulted in a steady stream on inquiries to the Biology Project from mothers, grandmothers, and children inquiring about the possible blood type of the father of a given child.

  • Here is a typical inquiry: I have been reading your info about inheritance of blood types and I am getting very confused! I am trying to figure out what blood type the father of my son could have since my son and I are both type A+.
  • Also, my brother is type 0 and my mom is A+.
  • We can’t find anything that explains how this can be.

Could you please help??? -From a concerned Mom in Alberta, Canada The Human ABO markers: The A, B, and O alleles Human blood type is determined by co-dominant alleles. An allele is one of several different forms of genetic information that is present in our DNA at a specific location on a specific chromosome.

There are three different alleles for human blood type, known as I A, I B, and i. For simplicity, we can call these alleles A (for I A ), B (for I B ), and O (for i). Each of us has two ABO blood type alleles, because we each inherit one blood type allele from our biological mother and one from our biological father.

A description of the pair of alleles in our DNA is called the genotype. Since there are three different alleles, there are a total of six different genotypes at the human ABO genetic locus. The different possible genotypes are AA, AO, BB, BO, AB, and OO.

  • How are blood types related to the six genotypes? A blood test is used to determine whether the A and/or B characteristics are present in a blood sample.
  • It is not possible to determine the exact genotype from a blood test result of either type A or type B.
  • If someone has blood type A, they must have at least one copy of the A allele, but they could have two copies.

Their genotype is either AA or AO. Similarly, someone who is blood type B could have a genotype of either BB or BO. A blood test of either type AB or type O is more informative. Someone with blood type AB must have both the A and B alleles. The genotype must be AB.

Someone with blood type O has neither the A nor the B allele. The genotype must be OO. How are ABO alleles inherited by our children? Each biological parent donates one of their two ABO alleles to their child. A mother who is blood type O can only pass an O allele to her son or daughter. A father who is blood type AB could pass either an A or a B allele to his son or daughter.

This couple could have children of either blood type A (O from mother and A from father) or blood type B (O from mother and B from father). Since there are 4 different maternal blood types and 4 different paternal blood types possible, there are 16 differnt combinations to consider when predicting the blood type of children.

  • In the tables below, all 16 possible combinations are shown.
  • If you know the blood type of the mother and father, the possible blood types for their children can be found.
  • What about the Rh factor? Can a father of blood type A+ have a child who is blood type A-? The Rh factor genetic information is also inherited from our parents, but it is inherited independently of the ABO blood type alleles.

There are 2 different alleles for the Rh factor known as Rh+ and Rh-. Someone who is “Rh positive” or “Rh+” has at least one Rh+ allele, but could have two. Their genotype could be either Rh+/Rh+ or Rh+/Rh-. Someone who Rh- has a genotype of Rh-/Rh-. Just like the ABO alleles, each biological parent donates one of their two Rh alleles to their child.

  1. A mother who is Rh- can only pass an Rh- allele to her son or daughter.
  2. A father who is Rh+ could pass either an Rh+ or Rh- allele to his son or daughter.
  3. This couple could have Rh+ children (Rh- from mother and Rh+ from father) or Rh- children (Rh- from mother and Rh- from father).
  4. Answering the Question from the Mother in Alberta, Canada The mother in question is blood type A+.

Her genotype at the ABO location is either AA or AO. Her Rh genotype is either Rh+/Rh+ or Rh+/Rh-. The information that the maternal grandmother is also blood type A+ and a brother is blood type O tells us that the maternal grandmother of the child has genotype AO, since she is type A but donated an O allele to one of her children.

  • The mother wants to know the potential blood types of the father of her son.
  • The son is blood type A+.
  • Unfortunately for this particular case, the mother cannot distinguish between any potential fathers from blood type alone.
  • Note from the table that this mother could have created a child with type A blood with a father of any of the four possible blood types, typeA, type AB, type B, or type O.

Likewise, the father of the child could be either Rh+ or Rh-. It should be apparent from this discussion that blood type is not a very good test for paternity. In some cases, unambigous information can be obtained, i.e. a type AB male cannot father a type O child.

  1. However in most cases, the results are uncertain.
  2. If determining the paternity of a child is important, there are very sensitive DNA test currently available that can establish paternity to a certainty in excess of 99.99%, or exclude someone as the biological father with absolute certainty.
  3. Elsewhere in the Biology Project is an excercise to follow the inheritance of DNA markers in a paternity study,

Blood Type Look-Up Tables

Mother’s Blood Type Possible Mother’s Genotype Father’s Blood Type Possible Father’s Genotype Possible Child Blood Type


Mother’s Blood Type Possible Mother’s Genotype Father’s Blood Type Possible Father’s Genotype Possible Child Blood Type AB AB A AA, AO A, AB, B AB AB AB AB A, AB, B AB AB B BB, BO A, AB, B AB AB O OO A, B


Mother’s Blood Type Possible Mother’s Genotype Father’s Blood Type Possible Father’s Genotype Possible Child Blood Type B BB, BO A AA, AO A, AB, B, O B BB, BO AB AB A, AB, B B BB, BO B BB, BO B, O B BB, BO O OO B, O


Mother’s Blood Type Possible Mother’s Genotype Father’s Blood Type Possible Father’s Genotype Possible Child Blood Type O OO A AA, AO A, O O OO AB AB A, B O OO B BB, BO B, O O OO O OO O

Is eye color a trait or phenotype?

Introduction – In the most elementary form, the inheritance of eye color is classified as a Mendelian trait.1 On the basis of the observation of more than two phenotypes, eye color has a more complex pattern of inheritance. Eye color ranges include varying shades of brown, hazel, green, blue, gray, and in rare cases, violet and red.

The traditional view was correct in which an allele that codes for brown is dominant over green or blue, and green takes precedence over blue.2 Melanocytes in the stroma and anterior layers of the eye hold melanin in their cytoplasms. In the rest of the body, the melanin is secreted from the cells. This provides an explanation why some babies develop their eye color, but skin pigmentation changes constantly throughout life.

Despite the color of the eye, the number of melanocytes does not differ. The quantity and quality of melanin in the cytoplasm determines the observed color of the eye. When light passes through a large amount of melanin, most of the visible light is absorbed, and the little that is reflected back appears brown.

This same phenomenon is the reason why the pupil appears black. All visible light is absorbed by the retina. As the eye color lightens, less melanin is present in the cells, reflecting more of the visible spectrum. Red and violet eyes come from a lack of pigment. The red appearance is the reflection of the eye’s blood vessels.

When there is too little pigment to produce a strong blue color, the red reflections interact with the small amount of blue, producing a violet color.3 The biological process for producing melanin, melanogenesis, involves numerous protein interactions.

In melanocyte-specific organelles known as melanosomes, two pathways for melanogenesis occur. One leads to eumelanin, a darker pigment (brown-black), and the other to pheomelanin, a light pigment (red-yellow). Tyrosinase (TYR), the enzyme responsible for pigment production in the body, starts the synthesis of both types of melanin by catalyzing a reaction between tyrosine and dopa, forming dopaquinone.

In the presence of cysteine, the reaction will proceed to form pheomelanin. To form eumelanin, dopachrome tautomerase, TYR, and TYR-related protein 1 complete the chemical pathway from dopaquinone.3 Although the aforementioned proteins are responsible for the production of melanin, once it has been produced in the melanosomes, other proteins are responsible for melanin maturation.

Membrane-associated transporter protein and p protein oculocutaneous albinism II (OCA2) transport melanosomes for melanin maturation. Melanocortin 1 receptor (MC1R) instructs a melanocyte to switch production between eumelanin and pheomelanin.3, 4, 5 Therefore, these two proteins affect the quality and quantity of the melanin in the cell.

Other very minor genes are responsible for eye color production, such as agouti signaling protein, but they usually have miniscule effects.5

Is brown eyes a gene or allele?

Eye color inheritance pattern – Due to the number of genes involved in eye color, the inheritance pattern is complex. Although a child’s eye color can generally be predicted by looking at the color of the parents’ eyes, the polymorphisms that can arise mean a child may well have an unexpected eye color.

A child’s eye color depends on the pairing of genes passed on from each parent, which is thought to involve at least three gene pairs. The two main gene pairs geneticists have focused on are EYCL1 (also called the gey gene) and EYCL3 (also called the bey2 gene). The different variants of genes are referred to as alleles.

The gey gene has one allele that gives rise to green eyes and one allele that gives rise to blue eyes. The bey2 gene has one allele for brown eyes and one for blue eyes. The allele for brown eyes is the most dominant allele and is always dominant over the other two alleles and the allele for green eyes is always dominant over the allele for blue eyes, which is always recessive.

  • This means parents who happen to have the same eye color can still produce a different eye color in their child.
  • For example, if two parents with brown eyes each passed on a pair of blue alleles to their offspring, then the child would be born with blue eyes.
  • However, if one of the parents passed on a green allele, then the child would have green eyes and if a brown allele was present, then the child would have brown eyes irrespective of what the other three alleles were.

Chromosome 15 – Eye colour However, this does not explain why two parents with blue eyes can have a child with brown eyes. It also does not explain how grey or hazel eyes arise. This is where modifier genes, other genes associated with eye color and mutations all come into picture, as they can all lead to variability in eye color.

Is red eyes a phenotype?

There are two different genotypes that code for the red- eyed phenotype (XRXR, XRXr) in females. Males have one genotype that codes for red eyes, XRY. Thus, the Red-eyed Male’s genotype can be determined from its phenotype.

Is brown eyes a genetic trait?

Eye colors are passed down through generations, but sometimes genetic variations can lead to surprising results in eye colors. Learn about the genetics of eye color in this guide. Whether eyes are blue or brown, eye color is determined by genetic traits handed down to children from their parents.