Agene is a sequence oDNA orRNA that codes for a molecule that has a function. Ingene expression, the DNA is firstcopied intae RNA. The RNA can bedirectly functional or be the intermediatetemplate for aprotein that performs a function. The transmission o genes tae an organism'saffspring is the basis o the inheritance ophenotypic traits. Thir genes mak up different DNA sequences criedgenoteeps. Genoteeps alang wi environmental an developmental factors determine whit the phenoteeps will be. Maist biological traits are unner the influence opolygenes (mony different genes) as well asgene–environment interactions. Some genetic traits are instantly veesible, sic asee colour or nummer o limbs, an some are nae, sic asbluid teep, risk for speceefic diseases, or the thoosands o basicbiochemical processes that constitutelife.
Genes can acquiremutations in thair sequence, leadin tae different variants, kent asalleles, in thepopulation. Thir alleles encode slichtly different versions o a protein, that cause differentphenoteepical traits. Uissage o the term "haein a gene" (e.g., "guid genes," "hair colour gene") teepically refers tae conteening a different allele o the same, shared gene. Genesevolve due taenaitural selection orsurvival o the fittest o the alleles.
The concept o a gene conteenas tae be refined as new phenomena are diskivert.[1] For ensaumple,regulatory regions o a gene can be faur remuived frae itscodin regions, an codin regions can be split intae severalexons. Someviruses store thairgenome inRNA instead o DNA an some gene products are functionalnon-codin RNAs. Tharefore, a braid, modren wirkin defineetion o a gene is ony discrete locus o heritable, genomic sequence that affect an organism's traits bi beinexpressed as a functional product or biregulation o gene expression.[2][3]
The termgene wis introduced biDensbotanist, plant pheesiologist angeneticistWilhelm Johannsen in 1905.[4] It is inspired bi theauncient Greek: γόνος,gonos, that means affspring an procreation.
