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

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYPrinciples of Inheritance and Variation1 Mark
Question
For question two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
Assertion: Complementary genes are non-allelic genes.
Reason: Complementary genes interact to produce a completely new trait.
✓

Answer

  1. Both assertion and reason are true but reason is not the correct explanation of assertion.

Explanation:

Complementary genes are those non-allelic genes which independently show a similar effect but produces a new trait when present together in the dominant form. W. Bateson and R.C. Pun nett observed that, when two white flowered varieties of sweet pea, Lathyrus odoratus were crossed, F1 progeny had coloured flowers. When F2 progeny obtained from F1 was classified, plants with coloured flowers and those with white flowers were obtained in 9 : 7 ratio. The two dominants are brought together in F1 generation and therefore coloured flowers are produced.

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