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NEETZoologyPrinciples of Inheritance and Variation

In pea plants, a single gene 'B' controls both seed shape and the size of starch grains. The heterozygote ( Bb ) produces round seeds, but the starch grains produced are of intermediate size. Which two genetic phenomena are illustrated by this single gene?

Options

  1. APleiotropy and Co-dominance
  2. BPleiotropy and Incomplete dominance
  3. CPolygenic inheritance and Incomplete dominance
  4. DComplete dominance and Polygenic inheritance

Correct answer

B. Pleiotropy and Incomplete dominance

Step-by-step solution

The gene 'B' controls two distinct traits: seed shape and starch grain size. The ability of a single gene to produce multiple phenotypic effects is known as pleiotropy. For seed shape, the Bb heterozygote produces round seeds, showing that the 'B' allele is completely dominant over 'b'. However, for starch grain size, the Bb heterozygote produces grains of intermediate size compared to the large grains of BB and small grains of bb . This intermediate phenotype in the heterozygote is a classic example of incomplete

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