Gene

A gene is the basic unit of genetic information (the basic unit of heredity). It is a certain stretch of DNA (sequence of nucleotides) on a chromozome.

General characteristics of the gene

 * a gene can occur in different forms – alleles
 * we refer to the set of all alleles in the cell of a given individual as genotype
 * the set of all the DNA of a given organism is called the genome
 * the human genome consists of a nuclear genome and an extranuclear genome (mitochondrial)
 * genes are arranged linearly on chromosomes and their specific location (locus) is unchanging
 * all genes on one chromosome form a linkage group
 * it includes so-called exons and intrones (cut out during DNA editing)

Gene species

 * genes can be divided into two basic groups according to function:
 * 1) Structural genes –  encode the primary structure of proteins, such as proteins with a biochemical, physiological or structural function
 * 2) Genes for functional RNAs –  their products, unlike structural genes, are not translated.
 * They are mainly genes for tRNA and rRNA (more about tRNA and rRNA on the RNA page).

Gene function

 * one gene can condition the creation of one specific trait ( monogenic inheritance )
 * the determination of one trait by one gene occurs more rarely than the realization of a trait after the interaction of a larger number of genes (oligogenic, or  polygenic inheritance)
 * more often, the formation of a trait depends on gene interactions, i.e. the specific form of the trait is determined by the alleles of several participating genes
 * another example of the multifacetedness of genetic information is the so-called gene families – gene family is a group of genes with a similar sequence that have the same or similar biological function

Related articles

 * Alleles
 * Phenotype
 * Genome
 * Genotype
 * Locus
 * Gene structure and function
 * Transcription
 * Types of inheritance
 * Traits