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NEETZoologyPrinciples of Inheritance and Variation

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In human skin colour, an individual with genotype AaBbCc will have an intermediate skin colour between the darkest and the lightest. Reason (R): In polygenic inheritance, the phenotype reflects the contribution of each dominant allele, showing an additive effect. In the light of the above statement

Options

  1. ABoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)
  2. BAssertion (A) is true but Reason (R) is false
  3. CBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
  4. DAssertion (A) is false but Reason (R) is true

Correct answer

C. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)

Step-by-step solution

Human skin colour is a well-known example of polygenic inheritance, controlled by three genes (A, B, and C). In polygenic inheritance, the phenotype is determined by the additive effect of each dominant allele. The darkest skin colour is produced by the genotype with all dominant alleles (AABBCC), while the lightest skin colour is produced by the genotype with all recessive alleles (aabbcc). An individual with the genotype AaBbCc has three dominant alleles and three recessive alleles. Due to the additive effect of

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