Question

Which one of the following cannot be explained on the basis of Mendel's law of Dominance?

• A. Alleles do not show any blending and both the characters recover as such in $F_2$ generation.
• B. Factors occur in pairs.
• C. The discrete unit controlling a particular character is called a factor.
• D. Out of a pair of factors, one is dominant and the other recessive.

Answer 1

The correct option is A Alleles do not show any blending and both the characters recover as such in $F_2$ generation.

According to the law of dominance, a heterozygous individual carries two contrasting alleles/ factors of a gene. Here only one allele can express itself in the individual. It is called as dominant allele. The allele which does not show itself in a heterozygous individual is known as recessive allele. Each character in an organism is controlled by a gene which has two alleles. Hence this law suggest that each character of an organism is represented by atleast two factors and that one allele (dominant allele) shows its effect in both homozygous and heterozygous condition while the other one (recessive) shows itself in homozygous condition only. Options B, C and D can be explained by this law. The law of segregation states that two alleles for one gene do not blend with each other.

So, the correct answer is 'Alleles do not show any blending and both the characters recover as such in F2 generation'.