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प्रश्न
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.
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उत्तर
(i) 1 : 2 : 1 - Phenotypic ratio
Suggest that the phenomenon is incomplete dominance
* When neither of the alleles of a character is completely dominant over the other and the F1 hybrid is intermediate between the two parents, the phenomenon is Incomplete dominance.
* The phenotypic and genotypic ratio in F2 generation is 1:2:1 in this case.
(ii) 3:1 - Phenotypic ratio
Suggest that the phenomena has monohybrid cross. Monohybrid cross is a cross which involves only a single pair of contrasting characters. The parental generation has genotype for pure gene which on cross produces homozygous progeny i.e. F1 generation. On selfing F1 generation obtain F2 generation. The F2 generation has phenotypic ratio 3 : 1.
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संबंधित प्रश्न
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.
Explain Mendel’s monohybrid progeny with the help of any one cross.
Differentiate Between Monohybrid and Dihybrid cross.
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 is the ratio of tall plants to dwarf plants in the F2 generation?
When a tall plant with rounded seeds (TTRR) is grossed with a Dwarf plant with wrinkled seeds (ttrr) the F1 generation consists of tall plants with rounded seeds. How many types of gametes the F1 plant would produce?
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.
Which pair of contrasting characters is studied in the pea plant monohybrid cross?
Which self-pollination is performed to obtain the F2 generation?
What is the phenotypic ratio in F2?
