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Introduction
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
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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.
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Blood Types
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There are three different alleles for human blood type:
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Blood types
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For simplicity,
we call these
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IA
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A
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IB
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B
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i
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O
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Genotypes
| 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.
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Allele from
Parent 1 |
Allele from
Parent 2 |
Genotype of
offspring
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Blood types
of
offspring
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A
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A
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AA
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A
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A
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B
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AB*
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AB
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A
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O
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AO
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A
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B
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A
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AB*
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AB
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B
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B
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BB
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B
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B
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O
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BO
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B
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O
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O
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OO
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O
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