Question

1. Define the following terms: allele, incomplete dominance, codominance, pleiotropy, epistasis. What are some examples of each?

Answer 1

Allele: allele is a varient of gene. Genes have different forms for example the hight of the plant denoted by the combination of two alleles long,dwarf.

Incomplete dominance: the dominant allele of a gene unable to mask effect of recessive allele in heterozygous condition than it is called as incomplete dominance. Example: red rose which is dominant allele mate white than the pink might be resulted due to incomplete dominance.

Codominance : if the two alleles of a gene character are equally expressed in heterozygous condition than they are Codominants. In human blood grouping iA and iB alleles are Codominants.

Pleotropy: if the gene is controlling two or more seemingly unrelated phenotypic traits than it is called as pleotropic gene and phenomenon is pleotropy. Sickle cell anemia and phenylketonuria are two diseases show pleotropy. They effect different organ systems at once.

Epistasis : the function of one gene is dependent on the functional status of one or more other genes is known as epistasis. The gene determines the other gene function is modifier gene.

Pigmentation in mice is dependent on the more than one gene, wild type phenotype here results only if all genes operated in the same pathway are operative correctly.