Question

A cross in which an organism showing a dominant phenotype crossed with the recessive
parent in order to know its genotype is called as a
A. Dihybrid cross
B. Monohybrid cross
C. Back cross
D. Test cross

Answer 1

Hint: Individuals genotype can be found by crossing it with an individual whose genotype is known. Genotype refers to the set of genes inherited by offspring from their parents. Phenotype is the actual characteristic appearance of the organism.

Complete step by step answer: The crossing of a phenotypically recessive individual with an individual which is used to determine the zygosity of the former by analyzing proportions of offspring phenotypes is called a test cross. In this cross, an organism showing a dominant phenotype is crossed with the recessive parent in order to determine the genotype of the organism.
-A cross between two different lines or genes that differ in two observed traits is called a dihybrid cross. It involves two pairs of contrasting characters. It is used to determine the genotype and phenotype of an organism.
-A cross between two organisms with different variations at one genetic chromosome of interest is called a monohybrid cross. In this cross, only one pair of contrasting characters is involved. In monohybrid cross the parent chosen is homozygous.
-The cross which involves the crossing of a hybrid with one of its parents or an individual which is genetically similar to its parent, in order to achieve offspring whose genetic identity is close to their parents is called a back cross. In this cross hybrids of the F1 generation are crossed with one of the parents.
So, the correct option is option D.
Note: Gregor Mendel was the first to introduce a test cross. Zygosity can be homozygous and heterozygous. Heterozygous is the one that has one dominant and one recessive allele. Homozygous dominant has two dominant alleles whereas those that are homozygous recessive consist of two recessive alleles.