Genetics and Evolution Notes


Genetics is the branch of science that deals with the study of genes, genetic variations and heredity in organisms. Genes are made up of DNA and are a type of genetic instruction. These instructions are used to make molecules and control the chemical reaction of life. These are passed from parent to offspring.


It is the process of heritable changes in the population of organisms over several generations. The inherited traits are the expression of genes that are copied and passed on to the offspring during reproduction. The heritable traits that are helpful for survival and reproduction become more common, while the harmful traits become rare.

Evolutionary Genetics

Evolutionary genetics is the study of how genetics leads to evolutionary change. It involves the study of the evolution of genome structure. It is the sum of population genetics and evolution.

Genome evolution is the process by which the size and structure of the genome change with time. The prokaryote genome evolves by mutation, transduction and horizontal gene transfer.

Also Read: Genetics

Mechanism of Genome Evolution

Gene Duplication

This is the duplication of a particular region of DNA. It occurs by recombination, aneuploidy, transposition, polyploidy and error in DNA replication.

Transposable elements

This refers to a region of DNA that can be inserted anywhere in the genome. For eg., Ty elements in Drosophila. Alu sequence is the most common transposable element found in humans.


Spontaneous mutations are responsible for changes in the genome. The nucleotide sequences change resulting in a frameshift mutation that alters the genome. This is more common in prokaryotes.

Exon Shuffling

During this, two exons from different genes come together. New genes are formed by this mechanism. Thus, a new gene is introduced into the genome.

Also Read: Evolution

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Frequently Asked Questions on Genetics and evolution notes


What are exons?

The part of DNA coding for amino acids is called exons. The prokaryotic DNA consists of exons only. The Eukaryotic DNA consists of both exons and introns.


How does horizontal gene transfer occur?

In prokaryotic organisms, horizontal gene transfer occurs by conjugation.


What is tetraploidy?

The duplication of chromosome set is called ploidy. Tetraploidy has four setsΒ of chromosomes.

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