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प्रश्न
A child has blood group O. If the father has blood group A and the mother has blood group B, work out the genotypes of the parents and the possible genotypes of the other offspring.
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उत्तर
If the father has blood group A, i.e., IAIA (homozygous), and the mother has blood group B, i.e., IBIB (homozygous), all offspring will have blood group AB (IAlB) rather than blood group O.

A child has blood group O only if both parents are heterozygous, i.e., father IAIi and mother IBIi.

Therefore, the parents of a child with blood group O will have genotypes IAi and IBi. A side from O blood group offspring, the child could have one of three other blood groups. They are IAi (blood group A), IBi (blood group B), and IAIB (blood group AB).
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संबंधित प्रश्न
Differentiate between the following:
Homozygous and Heterozygous
When a cross is made between tall plant with yellow seeds (TtYy) and tall plant with green seed (Ttyy), what proportions of phenotype in the offspring could be expected to be:
- Tall and green.
- Dwarf and green.
How would you find out whether a given tall garden pea plant is homozygous or heterzygous? Substantiate your answer with the help fo Punnett squares.
Given below are the F2 – phenotypic ratios of two independently carried monohybrid crosses :
(i) 1 : 2 : 1
(ii) 3 : 1
Mention what does each ratio suggest.
Explain Mendel’s monohybrid progeny with the help of any one cross.
Mention whether the cross is a monohybrid or dihybrid.
What is a monohybrid cross? How did Mendel perform this cross?
A certain couple got four daughters in a sequence and no son. Does it mean that the husband does not produce Y-chromosome bearing sperms? Explain. What is the chance of this couple having a daughter?
Name the conditions when both the alleles are identical?
A garden pea plant produces axial white flowers. Another of the same species produced terminal violet flowers. Identify the dominant trait?
Pure-bred tall pea plants are first crossed with pure-bred dwarf pea plants. The pea plants obtained in the F1 generation are then selfed to produce F2 generation of pea plants.
What do the plants of the F1 generation look like?
Give reasons why acquired characters are not inherited.
A Monohybrid cross is ______
Punnett square is used to know
Cross between hybrid and recessive parent:
In a monohybrid cross of plants with red and white flowered plants, Mendel got only red-flowered plants. On self-pollinating these F1 plants got both red and white flowered plants in 3:1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of parental generation.
In a cross between red coloured and white coloured flowers, when plants with red coloured flowers of F1 generation were self pollinated, plants of F2 generation were obtained in which 75% of plants were with red flowers and 2.5% plants were with white flowers.
Explain the inheritance of traits in the above cross with the help of a flow chart only along with the ratio of plants obtained.
Assertion (A): In humans, if gene (B) is responsible for black eyes and gene (b) responsible for brown eyes, then the colour of eyes of the progeny having gene combination Bb, bb or BB will be black only.
Reason (R): The black colour of the eyes is a dominant trait.
Given below is a schematic representation of the inheritance of the shape of the seeds of garden peas. Answer the questions that follow:

- Which is the dominant and recessive allele of the trait?
- What does the ratio 3 : 1 in the F2 generation represent?
- State Mendel's Law of Dominance.
Which pair of contrasting characters is studied in the pea plant monohybrid cross?
Which pure-breeding pea plants did Mendel select for plant height?
In the first filial generation, what is the observation for the cross \[TT \times tt\]?
Which self-pollination is performed to obtain the F2 generation?
Which gametes are produced by each \[Tt\] plant during selfing in F1?
What are the four genotypic outcomes of the cross \[Tt \times Tt\]?
Which conclusion follows from the tall and dwarf pea plant monohybrid cross?
