Differentiate between the following −
(a) Dominance and Recessive
(b) Homozygous and Heterozygous
(c) Monohybrid and Dihybrid.

Dominance

Recessive

1.

A dominant factor or allele expresses itself in the presence or absence of a recessive factor.

A recessive trait is able to express itself only in the absence of a dominant factor.

2.

For example, tall plant, round seed, violet flower, etc. are dominant traits in a pea plant.

For example, dwarf plant, wrinkled seed, white flower, etc. are recessive traits in a pea plant.

Homozygous

Heterozygous

1.

It contains two similar alleles for a particular trait.

It contains two different alleles for a particular trait.

2.

Genotype for homozygous possess either dominant or recessive, but never both the alleles. For example, RR or rr

Genotype for heterozygous possess both dominant and recessive alleles. For example, Rr

3.

It produces only one type of gamete.

It produces two different kinds of gametes.

Monohybrid Cross

Dihybrid Cross

1.

Monohybrid Cross involves cross between parents, which differs in only one pair of contrasting characters.

Dihybrid Cross involves cross between parents, which differs in two pairs of contrasting characters.

2.

For example, the cross between tall and dwarf pea plant is a monohybrid cross.

For example, the cross between pea plants having yellow wrinkled seed with those having green round seeds is a dihybrid cross.