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NEETZoologyPrinciples of Inheritance and Variation

What determines the darkness or lightness of the skin in a polygenic trait?

Options

  1. AThe presence of dominant alleles
  2. BThe number of each type of alleles in the genotype
  3. CThe environmental conditions
  4. DThe mutation of specific genes

Correct answer

B. The number of each type of alleles in the genotype

Step-by-step solution

In a polygenic trait the phenotype reflects the contribution of each allele, i.e., the effect of each allele is additive . To understand this better let us assume that three genes A, B, C control skin color in humans with the dominant forms A, B and C responsible for dark skin color and the recessive forms a, b and c for light skin color. The genotype with all the dominant alleles (AABBCC) will have the darkest skin color and that with all the recessive alleles (aabbcc) will have the lightest skin color. As expecte

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