Gene Interactions
When the expression of a single trait is influenced by two or more different non-allelic genes, it is termed as genetic interaction. According to Mendel's law of inheritance, each gene functions in its own way and does not depend on the function of another gene, i.e., a single gene controls each of seven characteristics considered, but the complex contribution of many different genes determine many traits of an organism.
Gene Expression
Gene expression is a process by which the instructions present in deoxyribonucleic acid (DNA) are converted into useful molecules such as proteins, and functional messenger ribonucleic (mRNA) molecules in the case of non-protein-coding genes.
Describe the function of activators and repressors.
Activators and repressors are the terms used for the transcription factors which are basically the proteins that regulate the expression of the genes. They bind to the nearby DNA and either activate or repress the transcription. The sites to which transcription factors bind are known as enhancers or silencers depending upon the regulation required. Basically, a transcription factor binds to a certain target sequence which makes it either easy or difficult for RNA polymerase to bind to the promoter of the gene.
ACTIVATORS:
Activators increase the transcription rate and instigate positive regulation of a gene. They help RNA polymerase to easily bind to the promoter of the operon. e.g. CAP which is a protein and in presence of cAMP, it binds to the promoter and increases the activity of RNA polymerase. However, when cAMP is absent, CAP does not bind to the promoter and the rate of transcription is low.
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