Genetics - Some Basic Fundamentals

  • Question

    Given below is a schematic diagram showing Mendel's experiment on sweet pea plants having axial flowers with round seeds (AARR) and terminal flowers with wrinkled seeds ( aarr). Study the same and answer the questions which follow:

    (i) Give the phenoeype of F1 progeny.
    (ii) Give the phenotypes of F2 progeny produced upon by the self-pollination of F1
    (iii)Give the phenotypic ratio of F2 progeny.
    (iv)Name and explain the law induced by Mendel on the basis of the above


    (i) All F1 progenies will have axial flowers and round seeds.

    (ii) F2 phenotypes will be

    • Axial flowers, round seeds (AARR, AARr, AaRr)

    • Axial flowers, wrinkled seeds (AArr, Aarr)

    • Terminal flowers, round seeds (aarr. aaRr)

    • Terminal flowers, wrinkled seeds (aarr)

    (iii) Phenotypic ratio of the F2 progeny: 9:3:3:1

    Axial flowers, round seeds- 9

    Axial flowers, wrinkled seeds - 3

    Terminal flowers, round seeds- 3

    Terminal flowers, wrinkled seeds- 1

    (iv) Law of segregation: When the two members of a pair of factors separate during the formation of gametes, they do not blend but segregate or separate into different gametes.

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