Main > Medical terms> Alleles


Alleles (Greek allelon – is mutual, each other; synonyms: genes are allelic, allels) – forms of a condition of the same gene which occupy identical loci of homologous chromosomes and cause phenotypical distinctions of individuals.


  • Dominant alleles – are equally shown in hetero - and a homozygous state and interfere with manifestation of other alleles of this gene at heterozygotes;
  • Alleles lethal (synonym: flew) – cause death of an organism carrier;
  • Multiple alleles – alleles of one gene which arise because of mutations and differ on the manifestation;
  • Alleles unstable – are characterized by high mutability, i.e. mutating much more often than the average level of natural mutations;
  • Alleles normal (synonyms: plus alleles, alleles of wild type) – usually dominant which cause development of a sign characteristic of the majority of the individuals making natural populations of a certain species;
  • Recessive alleles – are shown only in a gemizigotny or homozygous state;
  • Alleles sublethal – considerably reduce viability of organisms carriers.
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