Question

What is incomplete dominance? Give an illustration.

Answer 1

This is also known as semi dominance / partial dominance. These are seen when a heterozygous trait is expressed in an organism. The dominant and recessive traits blend together in such a condition. A mixture of both the traits is expressed in this condition.

Complete answer:
This is also known as semi dominance / partial dominance. These are seen when a heterozygous trait is expressed in an organism. The dominant and recessive traits blend together in such a condition. Incomplete dominance is a condition when both the dominant and recessive traits are not fully expressed. A mixture of both the traits is expressed in this condition. In a punnett square, when two RR flowers i.e homozygous trait is crossed with rr flowers, the resultant progeny is always heterozygous.
RR homozygous flowers are red in color
rr homozygous flowers are white in color.
The progeny Rr is seen pink in color i.e both the red and white has blended causing a medium color of the progeny.
RR: red petals (homozygous)
rr: white petals (homozygous)
Rr: pink petals (heterozygous)

Note:
A mixture of both the traits is expressed in this condition. This is also known as semi dominance / partial dominance. These are seen when a heterozygous trait is expressed in an organism. The dominant and recessive traits blend together in such a condition. The progeny Rr is seen pink in color i.e both the red and white has blended causing a medium color of the progeny.