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Human blood group is an example of which inheritance

How to write genotypes for blood types

The Inheritance of Blood Groups in Human: An Overvie

  1. The below mentioned article provides an overview on the inheritance of blood groups in man. Generally a gene has two alternative forms or alleles, one in each of the homologous chromosomes. If a gene has more than two alleles, it is known to exhibit multiple alleles
  2. Genetic classification of blood groups Inheritance of blood groups is controlled by three types of genes called alternatives (allels), from which the individual inherits one pair only that carried on that carried on the 9th chromosomes pair in all humans, these genes are symbolized by letters A, B and O
  3. These are present on the same locus of homologous chromosomes. eg:ABO blood group. C.Epistasis - A gene which masks the action of another gene is termed as epistasis. The gene is called epistatic gene and the gene whose effect is masked is termed as hypostatic gene. eg:Body colour of Mice. D.Pleiotropism - The ability of a gene to have a.
  4. ant, i.e. these will be expressed whenever the gene is present. The O gene is silent and only expressed when neither A nor B is present
  5. ant . so both A and B antigens will be expressed on the red cells whenever either alleles are present . hope it is your answer and I tried to tell you my best

Inheritance of blood group (AB) in humans & Steps of

Blood type is inherited based on the transfer of alleles from parents to offspring. Alleles are different forms of genes, which are pieces of DNA that carry genetic information. Blood type alleles.. Human blood type AB is an example of which pattern of inheritance? incomplete dominance. dominant/recessive. heterozygous Inheritance patterns of blood groups Blood groups are inherited from our parents in the same way as other genetic traits (eg, eye colour). ABO and Rh are the most well-known among the blood group systems

We inherit our sex (male or female) and blood group from our parents. Genetic disorders can also be inherited. Selective breeding occurs when humans breed plants and animals for specific.. - inheritance of ABO blood groups effect on animal blood corpuscles, but also on human blood corpuscles from different individuals'. The following year, in For example, blood of phenotype A 1 can represent one of several possible genotypes: A 1 A, A A 2, A 1 A 3, A 1 A x, A 1 A

Genetics since mendel

The human ABO blood type is a good example of multiple alleles. Humans can have red blood cells that are of type A (I A), type B (I B), or type O (i). These three different alleles can be combined in different ways following Mendel's Laws of Inheritance. The resulting genotypes make either type A, type B, type AB, or type O blood Mendel's Law of Dominance: Mendel's Law of Dominance states that if an organism is heterozygous for a certain trait (1 dominant + 1 recessive allele), only the phenotype associated with the. Inheritance of Blood Groups. In this section, we will briefly describe several general principles that apply to how most blood groups are inherited. Most blood group genes are co-dominant. For example, in the ABO system, A and B genes are co-dominant; in the Rh system, C and c are co-dominant; and in the Kell system, K and k are co-dominant. Blood type is determined by the alleles that we inherit from our parents. Alleles are different possible types of a particular gene, in this case the gene (s) controlling our Blood type. There are three common Blood type alleles: A, B, and O. We all have two alleles, one inherited from each parent The majority of human genes are thought to have more than two normal versions or alleles. Traits controlled by a single gene with more than two alleles are called multiple allele traits. An example is ABO blood type. Your blood type refers to which of certain proteins called antigens are found on your red blood cells

ABO blood grouping in humans is an example o

  1. ant inheritance. ABO blood groups are an example of blending inheritance. Crossing a B blood type with itself can sometimes yield blood type O. We can use a Punnet square to predict inheritance of ABO blood group phenotypes. The O blood group has a homozygous genotype. There is no do
  2. For example, none of what you read about above deals with the Rh system, which is connected to blood types like A+, B-, O+, etc. To learn more about Blood type and its inheritance, follow these links (or other ones that you find on your own: let me know if you find something good
  3. The ABO blood group system is the best known human blood group system. Antigens in this system are glycoproteins. (\PageIndex{4}\): Example of ABO blood group inheritance. A male who is type A (genotype of AO) and a female who is type B (genotype BO) can have children with blood types: A, AB, B, and O. For example, people with blood.
  4. Blood groups are inherited from both parents. The ABO blood type is controlled by a single gene (the ABO gene) with three types of alleles inferred from classical genetics: i, IA, and IB. The I designation stands for isoagglutinogen, another term for antigen

Inheritance and genetic of blood group 1. The Blood Group Systems Inheritance and Genetics Nawsherwan sadiq 2012-2013 2. •The blood group you belong to depends onwhat you have inherited from your parents. 3 Multiple Alleles (ABO Blood Types) and Punnett Squares An example of multiple alleles is the ABO blood-type system in humans. In this case, there are three alleles circulating in the population Codominance means that neither allele can mask the expression of the other allele. An example in humans would be the ABO blood group, where alleles A and alleles B are both expressed. So if an individual inherits allele A from their mother and allele B from their father, they have blood type AB. Suzanne Hart, Ph.D This paper will work towards the discussion of inheritance of human blood groups. An Overview of Blood Groups Blood grouping involves the use of ABO system as described by Karl Landsteiner. The grouping came into existence in the year 1900 after discovery by Nobel Prize winner Karl Landsteiner. He first discovered three blood types A, B, and O.

What are the two inheritance patterns of blood type

Human blood types are an example of what types of inheritanc

A person has one of the four blood groups: A, B, AB or O. This blood group system is controlled by a gene which has three different forms denoted by the symbols I A, I B and 1°. The genes I A and I B show no dominance over each other, that is, they are co dominant. However, genes I A and I B both are dominant over the gene 1°. In other words, the blood gene I° is recessive in relation to. Abo Blood Groups In Human Beings. K. Landsteiner (1900) has given the concept of ABO blood groups, on the basis of presence or absence of certain antigens. It was found that there are two antigens A or B and as a result of these, four groups of blood are present. With these antigens, there are two types of antibodies in the serum of the blood Justify 'human blood group is an example of co-dominance , complete dominance , multiple allelism ? - 7274101 ksheraz8908 ksheraz8908 25.12.2018 Biology Inheritance pattern of ABO blood groups in humans show dominance , codominance and multiple allelism can be explained as In dominance, F1 progeny resembles one of the parent.. - inheritance of ABO blood groups effect on animal blood corpuscles, but also on human blood corpuscles from different individuals'. The following year, in For example, blood of phenotype A 1 can represent one of several possible genotypes: A 1 A, A A 2, A 1 A 3, A 1 A x, A 1 A In human blood group there are four possible phenotypes A, B, AB & O. These blood groupings are controlled by gene I. There are three, instead of normally two, alleles of this gene namely I A, I B & i which control these four blood groups. Hence it is an example of multiple allelism. Out of these three alleles I A and I B are dominant over i.

The ABO blood grouping in human beings is an example for: i

Landsteiner and Levine (1927) divided human populations into three groups on the basis of reaction with anti-M serum and anti-N serum produced in rabbits. In honour of Landsteiner, the gene for this MN series was named as L and alleles as L M and L N, also now called M and N (Table 5.10). These alleles are co-dominant, so that the heterozygote L M L N gives rise to the blood group MN Blood Group Inheritance: Blood is determined by THREE alleles (A, B and O) and not two as for the other characteristics - this is termed multiple alleles The alleles A and B are co-dominant (both dominate equally) over O, which is recessive. The rhesus factor also plays a role in determining blood type: Rh-positive - is th ABO blood group system, the classification of human blood based on the inherited properties of red blood cells (erythrocytes) as determined by the presence or absence of the antigens A and B, which are carried on the surface of the red cells. Persons may thus have type A, type B, type O, or type AB blood. The A, B, and O blood groups were first identified by Austrian immunologist Karl.

justify 'human blood group is an example of co-dominance

  1. (a) ABO blood group is considered a good example of multiple alleles as it is controlled by I gene which has 3 alleles IA, IB and i. The three alleles govern the same character and hence show multiple allelism. (b) Homozygous mother having blood group A will have a genotype of- IAIAHomozygous father having blood group B will have a genotype of- IBIB A cross betweenThus the progeny will havethe.
  2. ed by the presence or absence of two antigens - A and B - on the surface of red blood cells. In addition to the A and B antigens, there is a protein called the Rh factor, which can be either present (+) or absent (-), creating the 8 most common blood types (A+, A-, B+, B-, O+, O-, AB+, AB-)
  3. Blood group O is the most common blood group. Almost half of the UK population (48%) has blood group O. Receiving blood from the wrong ABO group can be life threatening. For example, if someone with group B blood is given group A blood, their anti-A antibodies will attack the group A cells
  4. GENETICS OF HUMAN BLOOD TYPE Introduction surface antigen and antibody characteristics within the ABO blood group system. Table 1. The ABO Blood Types Blood Phenotype Blood Genotype Surface Antigen Present Antibody That Recognizes the Antigen For example, when

For example, a person of blood group A can receive blood either from group A or O as there are no antibodies for A and O in blood group A. As shown in the above table, individuals of blood group O are called as universal donors, whereas individuals of blood group AB are universal recipients. 2. Rh Blood Group Syste Human ABO markers. Blood types and genotypes? How are ABO alleles inherited by our children? Blood type & Rh factor calculator. Blood type calculator. Rh factor. Problem set: 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 Blood type calculator. Rh factor. Problem set: The Human Genetics Tutorial with problem solving exercises concerning the inheritance of the ABO blood group alleles has resulted in a steady stream of inquiries to the Biology Project from mothers, grandmothers, and children inquiring about the possible blood type of the father of a given child Codominance in Humans ╬ The most suitable incidence of codominant inheritance in humans is that of the inheritability of blood types. Human blood type follows the ABO system, which shows the occurrence of three different blood groups, namely, A, B, and O. Out of these, the alleles encoding the A and B blood group are dominant; whereas, that encoding the O group are recessive

The ABO blood groups in humans are expressed as the I A, I B, and i alleles. The I A allele encodes the A blood group antigen, I B encodes B, and i encodes O. Both A and B are dominant to O. If a heterozygous blood type A parent (I A i) and a heterozygous blood type B parent (I B i) mate, one quarter of their offspring are expected to have the AB blood type (I A I B) in which both antigens are. The ABO blood group system is the first described of the human blood groups based upon carbohydrate alloantigens present on red cell membranes. Anti-A or anti-B isoagglutinins (alloantibodies) are present only in the blood sera of individuals not possessing that specificity. This serves as the basis for grouping humans into phenotypes designated A, B, AB, and O. Blood group methodology to. Histo-blood group ABO system transferase is an enzyme with glycosyltransferase activity, which is encoded by the ABO gene in humans. It is ubiquitously expressed in many tissues and cell types. ABO determines the ABO blood group of an individual by modifying the oligosaccharides on cell surface glycoproteins. Variations in the sequence of the protein between individuals determine the type of. A child's blood group is 'O'. The parent's blood groups cannot be (a) A and B (b) A and A In human beings, inheritance of skin colour is due to multiple genes. This type of inheritance is called quantitative inheritance. moustaches and beard in human males are examples of (a) sex-linked traits (b) sex limited trait The human ABO blood groups are an example of multiple alleles, and the relationship between phenotype and genotype is depicted in the figure above.There are four possible phenotypic blood types for this particular gene: A, B, AB, and O. The letters refer to two specific carbohydrate molecules on the surface of red blood cells

Unit 6 Human Genetics

ABO Blood Group System. ABO blood grouping is based on the principle of an agglutination reaction. It is the popular method for blood group identification to determine the presence and absence of cellular antigens and their relative antibodies in the blood. In blood typing, the detection of antigen in the donor's RBCs is called forward typing Principles of Inheritance and Variation Class 12 Biology MCQs. 1. When 'Aa' is crossed with 'aa', (A is dominant over a) (a) all the offspring will have dominant phenotype. (b) all the offspring will have recessive phenotype. (c) 50% of offspring will have dominant phenotype and 50% will have recessive phenotype An example is the human ABO blood group system; persons with type AB blood have one allele for A and one for B. (Persons with neither are type O.) genetics Genetics , study of heredity in general and of genes in particular An example of codominance occurs in the ABO blood groups of humans. The A and B alleles are expressed in the form of A or B molecules present on the surface of red blood cells. Inheritance of the ABO blood system in humans is shown. An apparent example of this occurs with human skin color, which appears to involve the action of at least. The human ABO blood group provides an example of multiple alleles, and structure of the cell surface antigens for the three blood type alleles is shown in Figure 3.There are four possible phenotypic blood types for this particular gene: A, B, AB, and O. The letters refer to two specific carbohydrate molecules on the surface of red blood cells

Epistasis and Blood Groups in Man: In the ABO blood group system, a person with blood group A has antigen A on the surface of red blood cells; a blood group B person has B antigen: an AB person has both A and B antigens, whereas type O has neither A nor B antigen. The antigens are controlled by an autosomal gene I (iso-haemaglutinin) which has. Inheritance of blood groups. Blood groups in human are inheritable trait and are inherited from parents to offsprings on the basis of Mendel's Laws. Blood group inheritance depends on genes received from parents. Genes controlling blood group in man are three instead of two and are called multiple alleles (a) The inheritance of ABO blood groups in humans exhibits co-dominance and multiple allelism. Multiple allelism-: The ABO blood groups are controlled by the gene I. The I gene has three alleles, namely IA, IB and i. Since more than two alleles control a single trait thus it shows multiple allelism. Co-dominance-: The allele IA and IB are both dominant over the allele i but they express.

Closely related to incomplete dominance is codominance, in which both alleles are simultaneously expressed in the heterozygote. We can see an example of codominance in the MN blood groups of humans (less famous than the ABO blood groups, but still important!). A person's MN blood type is determined by his or her alleles of a certain gene The generation time is long. Pedigree analysis is the alternative method to study the inheritance of human traits in several generations. Question 18. A man with blood group A married a woman with a B group. They have a son with AB blood group and a daughter with blood group 0. Work out the cross and show the possibility of such inheritance The inheritance of ABO blood groups in humans exhibits dominance, codominance, and multiple allelism. In humans, the ABO blood groups are controlled by a gene called gene 'I'. It has three alleles, namely I A, I B and i. Dominance: The alles I A and I B are dominant over the allele i

Describe ABO blood groups as an example of complete dominance and codominance. Outline the differences in glycoproteins present in people with different blood types Human blood types are an example of both multiple alleles (A, B, O) and co-dominance (A and B are co-dominant) A. ABO blood group in humans. 1. Polygenic inheritance. B. Flower colour snapdragon. 2. Mendelian genetic disorder. Give an example of a plant, where the F2 progeny of a monohybrid cross has the same genotypic and phenotypic ratios. Write the technical term used in human ABO blood groups for IA, IB and i. [Delhi 2016C] Answer. A blood type (also called a blood group) is defined as the classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). A series of related blood types constitutes a blood group system, such as the Rh or ABO system. The frequencies of the ABO and Rh blood types vary from. An apparent example of this occurs with human skin color, which appears to involve the action of at least three (and probably more) genes. Cases in which inheritance for a characteristic like skin color or human height depend on the combined effects of numerous genes are called polygenic inheritance

PPT - Mendel, Genes, and Inheritance PowerPoint

The fourth and the rarest blood group 'AB' (universal recipient) was discovered in 1902 by two of Landsteiner's students Von De Castelle and Sturli. Bernstein in 1925 discovered that the inheritance of different blood groups in human beings is determined by a number of multiple allelic series What type of inheritance is demonstrated by human blood types? The only blood type known to be inherited is the ABO blood type. Your blood type is determined by genes on chromosome 9 and will. Describe the inheritance of ABO blood groups, specifying the role of multiple alleles. Multiple alleles are three or more alleles of the gene within the gene pool with the same traits. However a human can only have two alleles one from each parent. The blood type of a human has three alleles A, B and O of which only two can be inherited Codominance Inheritance. Codominance is a pattern of inheritance in which both alleles of a gene are always expressed. Our human blood type is a good example of codominance. Look at the table below that shows the four human blood types, distinguished by their red blood cells. A person with AB blood has both A and B antigens on their red blood. How is ABO blood type an example of the codominance inheritance pattern? The ABO blood group in humans, for instance, is determined by multiple alleles of a single gene. There are four possible phenotypes for this character: A person's blood group may be either A, B, AB, or O. These letters refer to tw

BLOOD GROUPS. At present, 33 blood group systems representing over 300 antigens are listed by the International Society of Blood Transfusion.[2,3] Most of them have been cloned and sequenced.The genes of these blood group systems are autosomal, except XG and XK which are X-borne, and MIC2 which is present on both X and Y chromosomes There are three blood genes: A, B, and O. (I'm going to ignore the + and - part of this.) A and B are dominant, and O is recessive. You inherit one blood gene from your mother and one from your father. The combination of genes determines your blood type. There are four possibilities: A, B, AB, and O. Here's how it works: A + A = A A + O = human blood consists of groups A ,B and O. however, there is one more blood group AB which contains alleles A and B in the same genotype what is this phenomenon called? A. coinheritance B. codominance C. incomplete dominance D. polygenic inheritance. Answer: B. codominance

Genetic diseases in humans example

Describe ABO blood groups as an example of complete dominance and codominance. Outline the differences in glycoproteins present in people with different blood types. 3.4.A2 Red-green color blindness and hemophilia as examples of sex-linked inheritance The ABO blood group is the most significant blood factor in clinical applications involving blood transfusions. With our recent ability to rapidly sequence genes, the ABO blood group is also proving to be a valuable asset for determining human migration patterns and origins

These combined with the ABO system of blood grouping may fall one among the eight blood group Types known as A+, A-, B+, B-, AB+, AB-, O+, or O-. Genetic Inheritance of Blood Types Similar to the characteristic traits that an individual inherits from his parents, so also is the blood Type, which has a genetic inheritance For example ABO blood group in humans. 15. It is said, that the harmful alleles get eliminated from the population over some time, yet sickle cell anaemia is persisting in the human population

Similarly, when discussing inheritance, the use of examples from human genetics to illustrate principles would be appropriate. For example, the inheritance of blood groups and similarities between blood group compatibility for tissue matching, and the immune response, could be discussed The Rh blood group is one of the most complex blood groups known in humans. From its discovery 60 years ago where it was named (in error) after the Rhesus monkey, it has become second in importance only to the ABO blood group in the field of transfusion medicine. It has remained of primary importance in obstetrics, being the main cause of hemolytic disease of the newborn (HDN) Polygenic inheritance should not be confused with the effects caused by multiple alleles. In the case of multiple alleles, a gene contains several different allele variants on the same locus of each chromosome, for example the three different alleles which control for blood type - A, B & O The ABO blood group in humans is determined by three different allelic forms I A, I B and i. The above three explanations prove that the inheritance of ABO blood group in humans shows dominance, co-dominance and multiple allelism So, what's a good example of a codominant inheritance in humans? The most common example is in regards to the AB blood type. Human blood type follows the ABO system, which refers to the three different blood groups: A, B, and O. The alleles encoding the A and B groups are dominant, and the O group is recessive. The results may be as follows

Multiple alleles

Other Patterns of Inheritance Flashcards Quizle

The ABO blood group system is the most important blood type system (or blood group system) in human blood transfusion. ABO blood types are also present in some other animals for example rodents and apes such as chimpanzees, bonobos and gorillas. 16/09/2015 6Mujtaba Ashraf 7 ABO blood group system. (b) Explain polygenic inheritance with the help of an example. 8. Describe the mechanism of inheritance of the ABO system of blood group highlighting the principle of genetics involved in it. 9. A homozygous tall pea plant with green seeds is crossed with a dwarf pe For example, with blood groups, the A allele is as 'strong' as the B allele. The A and B alleles are said to be co-dominant. Someone with one copy of A and one copy of B has the blood group AB. The inheritance pattern of children from parents with blood groups B (BO) and A (AO) is given in figure 3

Genetics Types of Inheritance Flashcards Quizle

Inheritance of ABO Blood Groups Follows Mendelian principles Blood group antigens are codominant- if the gene is inherited, it will be expressed. There are three allelic genes -A, B & O Some aberrant genotypes do occur but they are very rare. Understanding of basic inheritance important EX. ABO blood groups in human population: Four possible phenotypes for one character: A, B, AB, or O type. A, B, refer to two carbohydrates on the surface of red blood cells. A: A substance alone on the surface of RBC. B: B substance alone on the surface of RBC. AB: A and B substance, both exist on the surface of RBC

Blood Type Inheritance in Humans - Video & Lesson

The blood group in humans is a good example of non-Mendelian genetics codominance. Someone with the blood group AB expresses the allele of both blood groups A and B. Another example of Co-dominance Inheritance is in varieties of domestic fowl or chicken; in them, the varieties of black and white feathers are co-dominant and when the fowls of. Blood Typing/ Multiple Alleles. A number of human traits are the result of more than 2 types of alleles. Such traits are said to have multiple alleles for that trait. Blood type is an example of a common multiple allele trait. There are 3 different alleles for blood type, (A, B, & O). A is dominant to O. B is also dominant to O Inheritance of ABO and Rh blood groups. The inheritance pattern of the two types of blood group system (Table 2) is well established and is regularly used by the clinicians and epidemiologists. Immune response against ABO antigens. ABO oligosaccharide antigens are highly immune-potent and hence trigger the generation of antibodies The ABO blood type system is also an example of a trait that is controlled by more than just a single pair of alleles. In other words, it is due to a multiple-allele series. In this case, there are three alleles (A, B, and O), but each individual only inherits two of them (one from each parent) All ABOut Blood Types -Objectives • Identify the genetic mechanism for inheritance of the ABH blood group antigens, including the Bombay phenotype. • Differentiate the transferases and biochemical structures of the ABH antigens. • Evaluate the characteristics of and relationship between antigens an

Human blood type AB is an example of which pattern of

Antibodies. Human blood can be classified into different groups based on the reactions of red blood cells with blood group antibodies (Table 1). Naturally acquired antibodies, such as anti-A and anti-B antibodies, are normally found in serum from persons whose red blood cells lack the corresponding antigen For example, if a mutation that gave blood type O were actually 1 percent more beneficial than type A, it would take 100,000 generations to fix this mutation in the modern human population from a beginning population of 10,000 people. 7, 8 The larger the population at the time of the mutation, the longer it will take for fixation and the less. Human Inheritance •A family tree can be used to trace a particular trait through several generations. Human Blood Groups •There are three alleles for human blood groups -IA -IB -Io A modern example of evolution. ABO blood group system is an example for codominance. Allele A and allele B are codominant to each other. Hence, blood group AB is neither A nor B. It serves as a separate blood group because of the codominance between A and B. Another classic example of codominance is the tabby cat

Inheritance patterns of blood groups Australian Red

Inherited disorders are caused by a single gene mutation, such as ABO blood groups. With a few rare exceptions, most humans have one of the following four categories of blood types: A, B, AB, or O. Since the ABO blood group can be classified neatly into any of the four categories, it is considered a good example of a qualitative trait Such traits like a color of mice, eye color in mice and human blood groups are controlled by multiple alleles. In human populations the multiple alleles are widespread. For example in humans is now known at least 51 independent loci of blood groups with more than 70 alleles All humans and many other primates can be typed for the ABO blood group. There are four principal types: A, B, AB, and O. There are two antigens and two antibodies that are mostly responsible for the ABO types. The specific combination of these four components determines an individual's type in most cases. The table below shows the possible. What are multiple alleles? Give an example. Answer: When a gene expresses itself in more than 2 allelic forms, then the alleles are called multiple alleles. e.g: The gene 'I' controls the human blood group. It exist in 3 different alleleic forms i.e., I A, I B, and i, and is responsible for the four human blood groups viz, A, B, O and AB. Furthermore, the human ABO blood groups represent another deviation from Mendelian simplicity since there are more than two alleles (A, B, and O) for this particular trait. Deviations from Mendelian inheritance are also observed in traits with phenotypes having variable penetrance and expressivity

Blood type is the most common example of this as it does have three alleles, specifically A, B, and o blood types. Each of these controls the production of different antigenic substances on the surface of red blood cells. In this case both A and B are dominant and in the case of AB blood type codominance occurs Division of Medical Genetics. The Emory Clinic. 1365 Clifton Road. Clinic B, Suite 2200. Atlanta, Georgia 30322. (404) 778-8570 For patient-related questions and/or schedule an appointment. (404) 778-8562 Fax The most common example of codominance is the AB blood type. If a person with A type blood and a person with B type blood have a child, that child could have type AB blood where both phenotypes are fully expressed. Examples of Incomplete Dominance and Codominanc A variation on incomplete dominance is codominance, in which both alleles for the same characteristic are simultaneously expressed in the heterozygote. Codominance can also be seen in human blood types: the AB blood type is a result of both the I A allele and the I B allele being codominant. (An A blood type would only have the I A allele, and a B blood type would only have I B allele. THE INHERITANCE OF HUMAN TRAITS HUMAN BLOOD GROUPS Some genes can have three or more alleles: multiple alleles Important to remember that only two alleles are present in a 2N cell. ABO blood groups: Austrian physician Karl Landsteiner classified blood into four groups based on the presence or absence of specific chemical substances