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Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYPrinciples of Inheritance and Variation4 Marks
Question
  1. You are given tall pea plants with yellow seeds, whose genotypes are unknown. How would you find the genotype of these plants? Explain with the help of cross.
  2. Identify A, B and C in the table given below:
Pattern of Inheritance
Monohybrid F1 Phenotypic Expression
Codominance
‘A’
‘B’
Progeny resembled only one of the parents.
Incomplete dominance.
‘C’
✓

Answer

  1. The given tall pea plant with yellow seeds need to be crossed with a dwarf plant with green seeds:
  1. The dominant traits are tallness and yellow colour of seeds. The recessive traits are dwarfness and green colour of seeds.
  2. Cross between tall plant/ yellow seeds and dwarf plant/green seeds. Cross showing heterozygous nature for both traits.

In this cross, the F-generation shows four phenotypes in the ratio of 1 : 1 : 1 : 1. So, the given plant is heterozygous for both the traits.

  1.  

 A - Dominant trait.

B - Dominance.

C - Phenotype obtained in between of two parental traits.

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