Homozygous | Heterozygous |
It is pure for a trait and breeds true i.e., gives rise to similar homozygous individuals. | Heterozygous individual is seldom pure and produces offspring with different genotypes on selfing, eg., TT, Tt and tt on selfing of Tt individuals. |
Both the alleles of a trait are similar, e.g., TT,tt | It carries dissimilar alleles, e.g., Tt |
Homozygous individual can carry either dominant or recessive alleles but not both. | Heterozygous individual has both dominant and recessive alleles. |
It produces one type of gametes. | It produces two types of gametes. |
It does not show extra vigour. | The individual can show extra vigour called hybrid vigour or heterosis. |