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प्रश्न
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.
उत्तर
A plant with pure red flowers will generate plants with red blooms when crossed with a plant with pure white flowers. It is called Mendel's Monohybrid cross.
- Phenotypic ratio: Red : White : 3 : 1
- Genotypic ratio: Pure Red : Hybrid Red : Pure White : 1 : 2 : 1
संबंधित प्रश्न
Differentiate between the following -
Monohybrid and Dihybrid.
When a cross in 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.
A child has blood group O. If the father has blood group A and mother blood group B, work out the genotypes of the parents and the possible genotypes of the other offsprings.
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.
Name the conditions when both the alleles are identical?
What do you understand by the terms phenotype and genotype?
Give reasons why acquired characters are not inherited.
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.
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.
