Question

Explain following.

a. Explain Mendel’s monohybrid progeny with the help of any one cross.

b. Explain Mendel’s dihybrid ratio with the help of any one cross.

c. Distinguish between monohybrid and dihybrid cross.

d. Is it right to avoid living with a person suffering from a genetic disorder?

Answer 1

a. Monohybrid cross is a cross between two parents that have one pair of contrasting characters; for example, if pea plant with yellow seed coat is crossed with pea plant having green seed coat then in the F1 generation all the plants produce yellow seeds.



b. Dihybrid cross is a cross between two parents that have two pairs of contrasting characters, for example, a plant having round and yellow seeds is crossed with a plant having green and wrinkled seeds.



c.

Monohybrid cross	Dihybrid cross
The cross in which only one pair of contrasting characters is involved is known as monohybrid cross.	The cross in which only two pairs of contrasting characters are involved is known as dihybrid cross.
A monohybrid cross is useful in determining the dominance of genes.	A dihybrid cross is useful in studying the assortment of the offspring.
example- a cross between tall and dwarf plant	example- a cross between tall plant having red flower and a dwarf plant having white flower

d. No, it is not right to avoid living with a person suffering from a genetic disorder. Genetic disorders are not communicable diseases that would be transmitted to people who come in contact with people with genetic disoders. Genetic disorders are caused by changes in DNA sequences which can only be passed from one generation to another under specific circumstances. Rather, we sholud support and accept people with such disorders, so that they can live a normal life.