Blood Group Probability Calculation
This question involves basic Mendelian genetics, specifically the ABO blood group system, which has three alleles: $I^A$, $I^B$, and $i$ (often represented as $I^O$). Alleles $I^A$ and $I^B$ are codominant, and both are dominant over $i$. Blood group 'O' has the genotype $ii$ ($I^O I^O$).
Determining Parental Genotypes
The mother is heterozygous for 'A' blood group. This means her genotype is $I^A i$ ($I^A I^O$). She has the 'A' antigen but also carries the recessive 'O' allele.
The father is heterozygous for 'B' blood group. This means his genotype is $I^B i$ ($I^B I^O$). He has the 'B' antigen but also carries the recessive 'O' allele.
Predicting Offspring Genotypes
We can use a Punnett square to determine the possible genotypes of the offspring. Each parent can produce two types of gametes:
- Mother: $I^A$ and $i$ ($I^O$)
- Father: $I^B$ and $i$ ($I^O$)
| $I^B$ | $i$ ($I^O$) | |
|---|---|---|
| $I^A$ | $I^A I^B$ | $I^A i$ ($I^A I^O$) |
| $i$ ($I^O$) | $I^B i$ ($I^B I^O$) | $i i$ ($I^O I^O$) |
Identifying the 'O' Blood Group Probability
The Punnett square shows four possible genotypes for the offspring:
- $I^A I^B$ (Blood Group AB)
- $I^A i$ ($I^A I^O$) (Blood Group A)
- $I^B i$ ($I^B I^O$) (Blood Group B)
- $i i$ ($I^O I^O$) (Blood Group O)
Each genotype has an equal probability of occurring, which is 1 out of 4, or 25%.
The genotype required for blood group 'O' is $ii$ ($I^O I^O$). This occurs in 1 out of the 4 possible combinations.
Therefore, the probability of having a child with blood group 'O' is 25%.
Similar Questions
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Important Questions from Genetics
- Which one of the following disorders is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule ?
- Match List I with List II :
List I List II A. Incomplete dominance I. Human skin colour B. Co-dominance II. Inheritance of flower colour in Antirrhinum sp. C. Pleiotropy III. Phenylketonuria disease in humans D. Polygenic inheritance IV. ABO blood groups
Choose the correct answer from the options given below : - Which of the following statements are true with reference to the sex-determination in honeybees ?
A. An offspring formed from the union of a sperm and an egg, develops as a female (queen or worker).
B. An unfertilized egg develops as a male by parthenogenesis.
C. A male has half the number of chromosomes than that of a female.
D. Males produce sperms by meiosis.
E. Honeybees have a haplodiploid sex-determination system.
Choose the correct answer from the options given below : - In which animal do haploid cells divide mitotically to produce gametes ?
- The sixth mutant codon of beta globin gene causing polymerization of Haemoglobin and change in RBC shape is
