Question

What is dihybrid cross? Give a suitable example and checkerboard method blunt?

Answer 1

Hint: A hybrid refers to an offspring who is a breed from combining the qualities of two organisms of different breeds, varieties, species, or genera This breeding takes place through sexual reproduction.

Complete answer:
When two organisms of different breeds, varieties, species, or genera cross with each other and produce new offspring through the method of sexual reproduction then the cross will be known as a hybrid cross. This hybridization also can be performed in the lab through the crossing of two different types of a gene.
There are two kinds of the hybrid cross. One is a monohybrid cross and the other is a dihybrid cross. A monohybrid cross can be defined as the hybrid of two individuals with homozygous genotypes i.e. the individuals bear the same two alleles for a gene.
A dihybrid cross can be explained as a breeding process that happens between two organisms which are identical hybrids for two traits. A dihybrid cross represents a cross between two organisms where both individuals are heterozygous for two different traits. In the case of a dihybrid cross, the parents bear a different pair of alleles for each trait. One parent provides a homozygous dominant allele and the other one provides a homozygous recessive allele.
If yellow seed colour represents by ‘Y’, green seed colour represents by ‘y’ for, round-shaped represents by seeds ‘R’, and wrinkled seed shape represents by ‘y’ then the parental genotype will be ‘YYRR’ which is yellow-round seeds and ‘yyrr’ which is green-wrinkled seeds. At F1 generation, the phenotype will be ‘YyRr’. And the F2 generation will be as follows:

	YR	yR	Yr	yr
YR	YYRR	YyRR	YYRr	YyRr
yR	YyRR	yyRR	YyRr	yyRr
Yr	YYRr	YyRr	YYrr	Yyrr
yr	YyRr	yyRr	Yyrr	yyrr

Additional information:
Mendel first explained the basic principles of heredity. In his experiment, he chooses a pair of contradicting traits together for crossing. He took the wrinkled-green seed and round-yellow seed and crossed them which results in only round-yellow seeds in the F1 generation. This shows that the round shape and yellow color of seeds are prime features. In this case, the wrinkled shape and green color of seeds are recessive traits. After the self-pollination in F1 progeny, they produced four different combinations of seeds in the F2 generation. These combinations were wrinkled-yellow, round-yellow, wrinkled-green seeds, and round-green and the phenotypic ratio is 9:3:3:1.

Note: A dihybrid cross is a type of hybrid cross that happens between two individuals that are both heterozygous for two different traits. As an example of a dihybrid cross if we choose the wrinkled-green seed and round-yellow seed and crossed them, in the F1 generation they produce only round-yellow seed and in the F2 generation they will produce wrinkled-yellow, round-yellow, wrinkled-green seeds, and round-green seeds and the phenotypic ratio will be 9:3:3:1.