allélek

Allélek is the Hungarian term for alleles in genetics. An allele is a variant form of a gene at a specific locus on a chromosome. Alleles arise by mutation and are inherited from parents. In diploid organisms, individuals typically carry two alleles per gene, one on each homologous chromosome; the combination is called the genotype. The phenotype is influenced by the interaction of alleles; some alleles are dominant, others recessive, but many show codominance or incomplete dominance. When two identical alleles are present, the genotype is homozygous; when two different alleles are present, it is heterozygous.

Allele variation contributes to genetic diversity within populations. Their frequencies can be described by the Hardy-Weinberg principle under ideal conditions, but real populations are affected by selection, mutation, migration, genetic drift, and mating patterns. Common examples include the ABO blood group system, where multiple alleles determine antigens on red blood cells.

In research and medicine, allelic variation is studied to understand traits and disease risk. Some variants may increase or decrease susceptibility to conditions, affect drug response, or influence traits such as height or metabolism. The term allélek captures the essential idea that genes often exist in multiple forms, each with potential functional consequences for the organism.