Question

1) Give two mechanisms by which new genes are introduced into a genome

2) in 20 words or less describe a "dominant-negative" mutation

3) explain the differences between an activator and inducer

Answer 1

Mechanisms of new gene introduced into genome are mutation, polyploidy, gene duplication, pseudogene, exon shuffling, transposable element etc.

1. Mutation:- due to spontaneous or induced mutation there is addition or deletion of base pairs or change in chemical composition there is activation of new gene in genome due to change in frames of DNA sequence.
2. Transposable elements:- also called jumping gene these are sequence with autonomous replication capacity are move in genome due to insertion or removal of these sequences there is change in nucleotide sequence of genome or sometime these element keep there some part in genome that may activate new gene sequences.

Dominant negative mutations have an altered gene product that acts antagonistically to the wild-type allele. These mutations usually result in an altered molecular function.

An inducer is a molecule that regulates gene expression. An inducer can bind to protein repressors or activators. To start or stop transcription

Activator is , a DNA-binding protein that regulates one or more genes by increasing the rate of transcription rate in cell