Question

The very rare Bombay blood phenotype in humans results in blood type O because of the lack of both the A and B antigens in individuals who are of hh genotype. This genotype results in blood type O regardless of the genotype at the unlinked I locus. If two parents are both of I A I B Hh genotype, what is the probability that their child will have type blood B

Answer 1

The probability that the child will have type blood B equals 3/16.

Step-by-step explanation:

Available data:

• Individuals with the rare Bombay blood phenotype lack both the A and B antigens in individuals and/or are of hh genotype.

• Cross between two parents that are both of I A I B Hh genotype

Cross: IAIB Hh x IAIB Hh

Gametes) IAH, IAh, IBH, IBh

IAH, IAh, IBH, IBh

Punnett square) IAH IAh IBH IBh

IAH IAIAHH IAIAHh IAIBHH IAIBHh

IAh IAIAHh IAIAhh IAIBHh IAIBhh

IBH IAIBHH IAIBHh IBIBHH IBIBHh

IBh IAIBHh IAIBhh IBIBHh IBIBhh

F1) Genotype

• 1/16 IAIA HH
• 2/16 IAIAHh
• 1/16 IAIAhh
• 2/16 IAIBHH
• 4/16 IAIBHh
• 2/16 IAIBhh
• 1/16 IBIBHH
• 2/16 IBIBHh
• 1/16 IBIBhh

Phenotype

• 3/16 Blood type A
• 6/16 Blood type AB
• 3/16 Blood type B
• 3/16 Blood type 0