Question

Distinguish between homozygous and heterozygous.

Answer 1

ANSWER :-

The distinguishable points between these homozygous and heterozygous genotypic combinations are listed below-

Homozygous :-

• Homozygous combinations of genes constitute genotypes that are made up of wild, original, non mutated, dominant genes only.
• Homozygous combinations are found in the progeny that are produced as a result of pure breeding or true breeding or genetic selfing of pure-line parents.
• The progeny produced through pure breeding are referred to as "Pure-line individuals".
• Examples of homozygous combinations are as follows-

1. In the context of height, TT (Homozygous tall) and tt (Homozygous dwarf).
2. In the context of colour of flowers, RR (Homozygous red) WW (Homozygous white).

Heterozygous :-

• Heterozygous combinations of genes constitute of genotypes that are made up of a mixture of both, wild, original, non mutated, dominant genes, and mutated, recessive genes.
• Heterozygous combinations are found in the progeny that are produced as a result of impure breeding or genetic crossing of pure-line parents.
• Only the wild, original, non mutated, dominant allele is able to express itself in phenotypes of such genotypic combinations.
• Examples of heterozygous combinations are as follows-

1. In the context of height, Tt (Heterozygous tall), heterozygous combinations can never produce dwarf plants.
2. In the context of eye colour Bb (Brown eyes), heterozygous combinations can never produce blue eyes.