Question

Epistatic gene differ from dominant gene in
(A) Epistatic gene is nonallelic
(B) Epistatic gene never expresses itself independently
(C) Epistatic and hypostatic genes are present at different loci
(D) All the above

Answer 1

Hint: The epistatic genes are the types of genes which decide the expression of a trait. The epistatic genes are non-allelic and they never express themselves independently. Also, both the epistatic and hypostatic genes are located at different loci.

 Complete Answer:
The epistatic gene masks another gene expression just like the dominant alleles masks its complementary recessive gene expressions. In simple words, a gene which masks the phenotypic consequences of any other gene is recognized as an epistatic gene and the gene subordinated to it is called a hypostatic gene. Albinism, lack of skin pigmentation, is mainly caused due to the epistatic gene and it also regulates the formation of skin color. In albinism, the genes which recognize the skin color are available but are not expressed. In genetics, the phenomenon in which the mutation of genes and their effects depends upon the existence or nonexistence of mutations in either one or more than one gene is called epistasis. In particular, the process of epistasis intends that the impact of a gene type is masked by another gene. It is identified by self-progeny of the filial two animals. For example, if animals of phenotype X generate progeny of phenotype X and Y, whereas animals of phenotype Y only generate progeny of phenotype Y, then in this case gene Y is found to be epistatic to gene X. However, gene X would be epistatic to gene Y if the vice-versa of the same case appears as true.In case of dominant genes the first and second allele exhibit dominance and recessive characters respectively.

Thus, option (D) is the correct answer.

Note: The alleles and their related traits are either autosomal recessive or dominant, if the genes are found over an autosome. Moreover, except a sex chromosome all the other chromosomes are refereed to be autosomes.