Question

In rabbits, black skin (B) is dominant over brown skin (b), and short hair (S) is dominant over long hair (s). All F1​ offsprings are heterozygous black-short haired. F1​ male crossed with F1​ female. In F2​ generation, what is the percentage of homozygous black-short haired offspring?
A)50%
B)12.5%
C)6.25%
D)18.75%

Answer 1

Dominant refers to the interaction of a gene's two copies. Individuals obtain from each parent two copies of each chromosome, known as alleles. One allele would be expressed if the alleles of a gene are different; it is the dominant gene. The other allele's influence, called recessive, is masked.

Complete answer:
The alleles of one gene segregate independently from the alleles of another gene, according to Mendel's law of separate assortment. The skin color alleles [B and b] would then segregate separately from the hair length alleles [S and s], resulting in the development of four forms of gametes by heterozygous dominant parent plants. The phenotypic proportion of 9:3:3:1 is provided by the combination of these gametes. For 9/16 plants with both dominant phenotypes, only one plant is homozygous dominant, so 1/16*100 = 6.25 percent is the proportion of homozygous black short haired offspring.

F1​ generation: BbSs X BbSs

Gametes	BS	Bs	bS	Bs
BS	BBSS	BBSs	BbSS	BbSs
Bs	BBSs	BBss	BbSs	Bbss
bS	BbSS	BbSs	bbSS	bbSs
bs	BbSs	Bbss	bbSs	bbss

Hence, the correct answer is option (C)

Note: A dihybrid cross identifies a mating experiment with two features of two species that are identically hybrid. A hybrid organism is a heterozygous organism, which suggests that at a certain genetic location, or locus, it bears two distinct alleles.