What are the alleles for human blood types?

What alleles make type A blood?

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.

Which allele for human blood type is recessive?

A single gene controls ABO blood type system with three alleles. Two of the alleles are dominant (“IA or A” for Blood Type A, “IB or B” for Blood Type B) and the third allele (“i or O” for Blood Type O) is recessive.

What are blood alleles?

Human blood type is determined by codominant alleles. There are three different alleles, known as IA, IB, and i. The IA and IB alleles are co-dominant, and the i allele is recessive. The possible human phenotypes for blood group are type A, type B, type AB, and type O.

What blood type is iAi?

(See How Gene Pools Work for more information.) The following genotypes will yield these blood types: • iAiA or iAi – Both genotypes produce the A protein (type A). iBiB or iBi – Both genotypes produce the B protein (type B). iAiB – This genotype produces the A and B protein (type AB).

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Why does blood type A have B antibodies?

Blood group B has B antigens with anti-A antibodies in the plasma. Blood group A has A antigens on the red blood cells with anti-B antibodies in the plasma. This combination of antigens and antibodies determine which blood type you can be safely given for medical purposes.

Does O blood have antibodies?

Correspondingly, the immune systems of people with type A blood develop antibodies for B antigens, people with type B blood have antibodies for A antigens, and people with type O blood have antibodies for both.

How many alleles does a person have?

Somatic cells contain two alleles for every gene, with one allele provided by each parent of an organism. Often, it is impossible to determine which two alleles of a gene are present within an organism’s chromosomes based solely on the outward appearance of that organism.

Which alleles are dominant?

A dominant allele is denoted by a capital letter (A versus a). Since each parent provides one allele, the possible combinations are: AA, Aa, and aa. Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.

Is controlled by three alleles ABO?

Human blood is controlled by three alleles that create the ABO blood types. A and B are co-dominant, while the third allele, O, is recessive to the other two alleles. Below are a number of parent combinations. For each, indicate whether it could produce the resulting child.