Mention and explain all the laws of Mendel with examples.

Asked by Shubhi Gupta | 11th Nov, 2013, 08:25: PM

Expert Answer:

(i) Law of dominance: It states that one factor in a pair may mask or prevent the expression of the other factor. The variety that appeared in F1 generation is dominant and that which did not appear in the F1 generation is recessive.

E.g. In pea plant, height of the stem is controlled by a pair of factors or genes (T or t). If Tt is present, the plant would be tall since tallness is dominant over dwarfness.

ii) Law of segregation: During gamete formation, the genes of a particular character separate and enter different gametes. This is the law of segregation. This law is also called the law of purity of gametes.

E.g. During gamete formation, the paired factors (Tt) present in the F1 plant segregate independently and enter different gametes. So, each gamete receives either T or t from the paired factors Tt, which are responsible for the expression of a single character.

iii) Law of independent assortment: This law is based on the dihybrid experiment. According to this law, the genes for each pair of characters separate independently from those of the other characters during gamete formation.

E.g. Consider a plant with yellow round seeds being crossed with another pea plant with green wrinkled seeds. During gamete formation of a dihybrid cross, the factors for yellow colour assort independently of the factors for round shape.

The gene Y may combine with the dominant gene R or the recessive gene r of the other character and enter a gamete. In the same way, the gene y may combine with the dominant gene R or the recessive gene r and enter a gamete. So, the F1 dihybrid plants produce four types of gametes and they are RY, rY, Ry and ry.

Answered by Sheetal Kolte | 12th Nov, 2013, 10:20: AM

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