Locus (plural: loci)
Definition
A defined physical position on a chromosome. In forensic genetics, 'locus' usually refers to a specific STR site used in profiling. The different sequence variants found at a locus across a population are called alleles.
Related terms
- Chromosome
- A discrete, condensed structure consisting of a single long DNA molecule complexed with histone proteins. Humans normally carry 46 chromosomes in 23...
- Gene
- A segment of DNA that encodes a functional product, most commonly a protein but also non-coding RNA molecules. Protein-coding genes occupy roughly...
- Heterozygosity
- The proportion of individuals in a population who carry two different alleles at a locus. A locus with high heterozygosity is more...
- Polymorphism
- The existence of two or more sequence variants (alleles) at a locus in a population at a frequency above one percent. High...
- Short tandem repeat (STR)
- Short repetitive DNA sequences scattered throughout the genome, with the number of repeats varying between individuals at each locus. DNA profiling compares...
Explained in
- Chromosomes, Genes and the Human GenomeA defined physical position on a chromosome. In forensic genetics, 'locus' usually refers to a specific STR site used in profiling. The different sequence vari...