Answer to Question #90898 in Genetics for SOO GIL

Question

Hello Sir,

I have a test regarding some questions as below.
It is very, very important for me, I hope I get some answer from a expert.

Question 1: " Explain the main type of interaction between alleles of different genes"
Question 2: "Explain the main type of interaction between alleles of one and the same gene"

Thanks in advance.

Best regards

Answer 1

1. There are several types of interactions between alleles of different genes: complementary factor, epistasis, inhibitory factor, etc. Complementary factor is one of the major types of gene interactions. Complementary interaction is a type of interaction of nonallelic genes where a trait is formed as a result of the combination of their dominant alleles. In other words, two genes that occupy different loci are complementary to each other. As a result, if each gene is present alone, they remain unexpressed. Both genes are crucial factors for their expression and presence of the phenotypic trait. For example, in sweet pea, two specific genes are required to produce anthocyanin pigment resulting in purple colour of flowers. Absence of any of the genes causes the absence of pigmentation.

2. The interactions between alleles of the same gene include complete dominance, incomplete dominance, co-dominance, etc. Co-dominance is a type of interaction between allelic genes in which the heterozygous phenotype differs from both the dominant homozygote phenotype and the recessive homozygous phenotype, and the heterozygous phenotype contains products of both genes. This type of gene interaction is observed during the formation of the IV blood group of the system (AB0) in humans. As a result, both type A and type B antigens are expressed on the surface of erythrocytes that results in the formation of the IV blood group.