Question

Which one of the following statements did not explained Mendel's law of dominance?

• A. In a pair of factors, one is recessive and other is dominant.
• B. Factors are in pairs.
• C. The contrasting character is controlled by separate unit called as factors.
• D. There is no blending of characters and both characters appear as it is in $F_2$ generation.

Answer 1

The correct option is D There is no blending of characters and both characters appear as it is in $F_2$ generation.

According to the law of dominance, each pair of a contrasting trait is governed by two determinants or factors; for example, plant contained two determinants for the characteristic of height. Factor “T” is responsible for tallness while “t” governs dwarfism. The allele/factor that can express itself in the heterozygous individual is called as the dominant trait. The other factor, whose effect is masked by the presence of dominant factor, is called recessive factor. The recessive factor is present in $F_1$ hybrid but is masked by a factor for the dominant trait and that’s why it produced both parental types in $F_2$ progeny. This explains option A. Law of segregation states that the two factors for a trait, present together in a heterozygous individual, do not get mixed and are separated during gametogenesis. Thus each gamete receives one allele for a trait and two types of gametes are formed; 50% gametes carry factor for dominance and 50% carry the recessive factor. These gametes are then randomly fused. Also known as the principle of purity as the segregation of two factors brings about the purity of gametes. Thus, the correct answer is option D.