allele

Definition

An allele is a variant form of a gene that arises through mutation and occupies a specific position (locus) on a chromosome. Each individual inherits two alleles for each gene, one from each parent. Alleles can be dominant, recessive, or codominant, determining how traits are expressed in an organism. Allelic variation is fundamental to genetic diversity within populations and underlies phenotypic differences between individuals. In genomics research, identifying and characterizing alleles is crucial for understanding disease susceptibility, drug response (pharmacogenomics), and evolutionary relationships. Single nucleotide polymorphisms (SNPs) represent the most common type of allelic variation, while structural variants like insertions, deletions, and copy number variations also create allelic diversity that impacts biological function and clinical outcomes.

Visualize allele in Nodes Bio

Researchers can use Nodes Bio to visualize allelic networks showing relationships between genetic variants, associated phenotypes, and affected biological pathways. Network graphs can map how different alleles of the same gene influence protein-protein interactions, connect allelic variants to disease outcomes, or display population-level allele frequency distributions across ethnic groups. This enables identification of functional relationships between alleles and downstream molecular consequences.

Example Use Case

A pharmacogenomics research team investigating warfarin dosing variability maps allelic variants of CYP2C9 and VKORC1 genes in a diverse patient cohort. Using network visualization, they connect specific alleles to metabolic enzyme activity levels, drug response phenotypes, and adverse event rates. The analysis reveals that patients carrying CYP2C9*2 or *3 alleles require significantly lower warfarin doses and shows how these alleles interact with dietary vitamin K intake and other genetic modifiers, enabling development of personalized dosing algorithms.

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