Question

Differentiate between Mendel’s monohybrid cross and dihybrid cross.

Answer 1

Hint: Mendel stated three fundamental laws which laid the base of genetics. He studied the genes characters and their inheritance into the offsprings. He conducted the experiments on pea in 1856 and established the laws in 1863.

Complete answer:
Gregor Mendel was a scientist who is known for his Fundamental laws of Inheritance. He stated that the genes come in pairs and are inherited as individual units from each parent. He studied the traits being dominant and recessive in the offspring.
His laws are- Law of dominance, the law of segregation and law of independent assortment.

Let us understand the terms:
> Monohybrid cross- It is the crossing between the organisms of different variations in the same genetic chromosome of interest. For example crossing of a long-stemmed pea with a short-stemmed pea.

> Dihybrid cross – Crossing between two different genes that differ in two traits. For example: examining two features of the pea plant, colour and shape, One dominant allele R will be for dominant round trait and r for recessive shape trait. Y will be for yellow colour and Y will be the recessive green colour.

Let us see the other differences between them.

Monohybrid cross	Dihybrid cross
It involves one parent.	It involves two parents.
It can produce a single progeny.	It is capable of producing two progenies also.
It involves organisms heterozygous for only one character.	It includes organisms heterozygous for two characters.
It is done for one generation.	It can be done for two generations.
It results in 3:1 phenotypic ratio.	It results in 9:3:3:1phenotypic ratio.
It shows genotypic ratio 1:2:1 in the F2 generation.	It shows genotypic ratio 1:2:1:2:4:2:1:2:1 in F2 generation.

Note: Mendel studied the characters in seven aspects- seed shape, flower colour, seed coat, pod shape, flower location, plant height and unripe pod colour. Mendel’s mathematical and statistical skills helped him to figure out the whole process. Crossing over is all a biological process occurring during the fertilization to maintain the gene pool. These distinct characters lay the base of existence of an offspring.