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Blood-Type Genetics. Blood Cell Antigens. Blood types are the result of the presence (or absence) of antigens (molecules) on the surface of the individual’s red blood cells. These fall into two groups: A , B , O blood type Rh factor. Codominance.
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Blood Cell Antigens Blood types are the result of the presence (or absence) of antigens (molecules) on the surface of the individual’s red blood cells. These fall into two groups: • A, B, O blood type • Rh factor
Codominance The gene for antigen A and the gene for antigen B are CODOMINANT. Both traits are expressed completely when the gene for A is inherited from one parent and the gene for B is inherited from the other parent.
Blood Type Problem Three children recently born in a hospital were accidently mixed up. The blood types of the parents involved are given along with the blood types of the infants.Determine which baby belongs with which parents, and explain your reasoning for the decisions you made. Mother and Father_____ _____Babies_______ Parents #1 Type A & Type B Child x Type A Parents #2 Type O & Type AB Child y Type O Parents #3 Type B & Type O Child z Type AB
Rh Inheritance Rh inheritance is independent of A, B, O blood type.
ABO and Rh blood type distribution by nation (population averages)
Blood Type Problem A man whose alleles for blood type are A/O and Rh+/Rh- marries a woman whose alleles are B/O and Rh+/Rh-. • What are the phenotypes of the parents with respect to blood type? • What are the possible genotypes for their offspring with respect to blood type? • What are the possible phenotypes for their offspring with respect to blood type?
What are the phenotypes of the parents with respect to blood type? • Father: • AO is expressed as type A • Rh+/Rh- is expressed as Rh+ • Father’s phenotype is A+ • Mother: • BO is expressed as type B • Rh+/Rh- is expressed as Rh+ • Mother’s phenotype is B+
What are the possible genotypes for their offspring with respect to blood type? Paternal gametes A/Rh+ A/Rh- O/Rh+ O/Rh- AB Rh+Rh+ AB Rh+Rh- BO Rh+Rh+ BO Rh+Rh- B/Rh+ AB Rh+Rh- AB Rh-Rh- BO Rh+Rh- BO Rh-Rh- B/Rh- Maternal gametes AO Rh+Rh+ AO Rh+Rh- OO Rh+Rh+ OO Rh+Rh- O/Rh+ AO Rh+Rh- AO Rh-Rh- OO Rh+Rh- OO Rh-Rh- O/Rh-
What are the possible phenotypes for their offspring with respect to blood type? AB+ = /16 AB- = /16 A+ = /16 A- = /16 B+ = /16 B- = /16 O+ = /16 O- = /16 3 AB Rh+Rh+ AB Rh+Rh- BO Rh+Rh+ BO Rh+Rh- 1 3 AB Rh+Rh- AB Rh-Rh- BO Rh+Rh- BO Rh-Rh- 1 AO Rh+Rh+ AO Rh+Rh- OO Rh+Rh+ OO Rh+Rh- 3 1 AO Rh+Rh- AO Rh-Rh- OO Rh+Rh- OO Rh-Rh- 3 1