Mendel's Principle (Law) of Dominance

Mendel's Principle (Law) of Dominance 

Law of Dominance states that one allele or pair of alleles, which control a character, usually expresses itself and prevents the expression of the other . The allele which expressed in a hybrid is called dominant allele and the other unexpressed one is recessive allele.

Explanation:- 

Cross a homozygous tall pea plant having the genotype TT with a dwarf pea plant having the genotype tt . F1 generation  consists only of tall plants, having genotype Tt. The expressed allele T for tallness is dominating over the unexpressed allele t for dwarfness. The fact that the allele for dwarfness is present in F1 plant can be verified by inbreeding them when F2 progeny will consist of both tall and dwarf plants in the ratio of 3:1.

Degree of Dominance:-

In pea 🫛 plant, Dominance is complete as the allele for tallness fully suppresses the expression of dwarfness whereas in the4 o'cloc
k plant, the flower colour shows incomplete dominance. Thus, the degree of Dominance in Law of Dominance is 1:2:1 i.e

3:1. 

The monohybrid cross which showing Law of Dominance in pea plant and in Guinea pig as expressed as follows:-