Question

The gene which masks the effect of the another gene is called as
A. Epistatic gene
B. Multiple allele
C. Lethal gene
D. Complementary gene

Answer 1

Hint: Gene is the basic functional structural unit of hereditary.
Genes are made up of DNA and they act as an instruction to make molecules known as proteins.
Alleles are the different or variant form of gene.
Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome.

Complete answer:
Epistasis is the non-allelic gene interaction where the presence of one gene masks the expression of another gene.
Dihybrid ratio for dominant epistasis becomes 12:3:1.
Recessive epistatic: It is the non-allelic gene interaction in which the presence of one recessive gene masks the expression of another recessive gene and their dihybrid ratio becomes 9: 3: 4.

Multiple alleles: It means presence of more than two alleles of a gene which can be dominant, incompletely dominant or codominant such as ABO blood group inheritance.

Complementary genes: They are the non allelic genes which have their independent effect but they produce a new trait when their dominant forms are present together.

A dihybrid cross of this type of gene is 9:7 phenotypic ratios.
Lethal genes: The genes that cause premature death of the organism.
If the gene is dominant, it kills heterozygotes, whereas recessive lethal genes kill homozygous recessive individuals.

Hence, the correct answer is option (A).

Note: The concept of epistasis originated in genetics in 1907 but is now used in biochemistry, computational biology and evolutionary biology. It arises due to interactions, either between genes (such as mutations also being needed in regulators of gene expression) or within them (multiple mutations being needed before the gene loses function), leading to non-linear effects.