Dominant:

(i) Dominant allele is able to express itself even in the presence of its recessive allele.

(ii) It does not require another similar allele to produce its effect on the phenotype, e.g., Tt is tall.

(iii) Dominant allele or factor can from complete polypeptide or enzyme for expressing its effects, e.g., red colour of flower in pea.

Recessive:

(i) Recessive allele or factor is unable to express its effect in the presence of dominant allele.

(ii) It produces its phenotypic effect only in the presence of a similar allele, e.g., tt is dwarf.

(iii) The recessive allele forms an incomplete or defective polypeptide or enzyme so that the expression consists of absence of the effect of dominant allele, e.g., white flower colour in pea.