Genes are sections of chromosomes, which in turn are sections of DNA that carry the hereditary information and are found in every cell, where a gene can be seen as the code of the cell. The physical location of genes is called the gene locus (gene locus).
Specific genes have specific tasks. The totality of genetic hereditary information is called the genome.
Genes can be in both coding regions (coding genes) and non-coding regions of DNA (non-coding genes).
Coding genes synthesize proteins via the intermediate messenger RNA (mRNA). The potential coding regions of DNA are referred to as the exome. 98% of all genes are non-coding. A large proportion are regularly transcribed and enable the synthesis of the mRNA, tRNA and rRNA as well as other ribonucleic acids. Although non-coding genes do not synthesize proteins and are often referred to as junk, they are due to positive evolutionary selection and are considered to have an advantage in terms of maintaining and minimizing biological properties. In addition, non-coding genes are considered genetic on/off switches and determine when and where genes are expressed.
Gene expression determines how genetic information is expressed and appears, i.e. how the genotype of an organism or cell is expressed as a phenotype.
In addition to coding and non-coding genes, there are also the so-called pseudogenes, i.e. sections of DNA that resemble a gene in structure but only act as a template of a functional protein. The origin of pseudogenes is assumed to be genes that have been rendered functionless by certain mutations. However, to the pseudogene there is usually still a functional variant.
Jumping genes, also called transposons, are considered to be a special type of gene. This is a section within the DNA, which is able to jump from one locus (gene locus) and to reinsert itself at another place in the genome. They are found exclusively in humans and are essential for the expression of genetic diversity.
A mutation within a gene can be either spontaneous (spontaneous mutation) or caused by environmental influences, such as radioactivity.