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प्रश्न
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?
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उत्तर
Daughter or son is a matter of chance for Y- or X-chromosome carrying sperm to fertilize the egg. It is always 50% The couple got four daughters as a matter of chance encounter of the X-chromosome carrying sperm fertilizing the eggs. The chance of the couple getting another daughter is again 50% (so is for the son).
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संबंधित प्रश्न
Differentiate between the following:
Dominance and Recessive
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.
Explain Mendel’s monohybrid progeny with the help of any one cross.
Differentiate Between Monohybrid and Dihybrid cross.
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 plant tallness is dominant over dwarfness and red flower is dominant over white. Starting with the parents work out a dihybrid cross. What is standard dihybrid ratio? Do you think the values would deviate if the two genes in question are interacting with each other?
Pooja has green eyes while her parents and brother have black eyes. Pooja’s husband Ravi has black eyes while his mother has green eyes and father has black eyes.
a. On the basis of the above given information, is the green eye colour a dominant or recessive trait? Justify your answer
b. What is the possible genetic makeup of Pooja’s brother’s eye colour?
c. What is the probability that the offspring of Pooja and Ravi will have green eyes? Also, show the inheritance of eye colour in the offspring with the help of a suitable cross.
OR
c. 50% of the offspring of Pooja’s brother are green eyed. With help of cross show how this is possible.
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.
