Gene

<p>In <a href="/facts/Biology/1M1ee3pB">biology</a>, the word gene has two meanings. The Mendelian gene is a basic unit of <a href="/facts/Heredity/t0aMmRWx">heredity</a>. The molecular gene is a sequence of <a href="/facts/Nucleotide/pQKEwlJI">nucleotides</a> in <a href="/facts/DNA/nB89Iauz">DNA</a> that is transcribed to produce a functional <a href="/facts/RNA/HxPeNfNj">RNA</a>. There are two types of molecular genes: protein-coding genes and non-coding genes. During <a href="/facts/Gene_expression/alCPohLR">gene expression</a> (the synthesis of <a href="/facts/Gene_product/GItmzEpH">RNA or protein</a> from a gene), DNA is first <a href="/facts/Transcription_(biology)/bDgp9HDN">copied into RNA</a>. RNA can be <a href="/facts/Non-coding_RNA/aXqyV5so">directly functional</a> or be the intermediate <a href="/facts/Protein_biosynthesis/P4IcGjPd">template</a> for the synthesis of a protein.
</p><p>The transmission of genes to an organism's <a href="/facts/Offspring/v7LD4qBl">offspring</a>, is the basis of the inheritance of <a href="/facts/Phenotypic_trait/seYSUTul">phenotypic traits</a> from one generation to the next. These genes make up different DNA sequences, together called a <a href="/facts/Genotype/MlzK1Mfz">genotype</a>, that is specific to every given individual, within the <a href="/facts/Gene_pool/kYRN6qIa">gene pool</a> of the <a href="/facts/Population_(biology)/ArxshNuB">population</a> of a given <a href="/facts/Species/oDg6b96r">species</a>. The genotype, along with environmental and developmental factors, ultimately determines the <a href="/facts/Phenotype/vxWXKGLj">phenotype</a> of the individual.
</p><p>Most biological traits occur under the combined influence of <a href="/facts/Polygene/wH8c6Cwm">polygenes</a> (a set of different genes) and <a href="/facts/Gene%E2%80%93environment_interaction/WCFHY5YW">gene–environment interactions</a>. Some genetic traits are instantly visible, such as <a href="/facts/Eye_color/50sYzD22">eye color</a> or the number of limbs, others are not, such as <a href="/facts/Blood_type/zdxFTV6F">blood type</a>, the risk for specific diseases, or the thousands of basic <a href="/facts/Biochemistry/fa2pWEBp">biochemical</a> processes that constitute <a href="/facts/Life/DNw7NUId">life</a>. A gene can acquire <a href="/facts/Mutation/Ee4NnWbY">mutations</a> in its <a href="/facts/Gene_sequence/e1swwPY6">sequence</a>, leading to different variants, known as <a href="/facts/Allele/8FxCS9KA">alleles</a>, in the <a href="/facts/Population/ArxshNuB">population</a>. These alleles encode slightly different versions of a gene, which may cause different <a href="/facts/Phenotypical/vxWXKGLj">phenotypical</a> traits. Genes <a href="/facts/Evolution/Hj0qAaBk">evolve</a> due to <a href="/facts/Natural_selection/JXTte6en">natural selection</a> or <a href="/facts/Survival_of_the_fittest/0HmV10AD">survival of the fittest</a> and <a href="/facts/Genetic_drift/lvoEEctX">genetic drift</a> of the alleles.
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Gene open-in-new

Gene