Heterozygosity
Definition
The proportion of individuals in a population who carry two different alleles at a locus. A locus with high heterozygosity is more informative for forensic profiling than one where most people carry the same allele. CODIS loci were selected partly for their high heterozygosity values.
Related terms
- Amelogenin
- A gene on both the X and Y chromosomes used for sex determination in forensic STR kits. The X-allele amplicon is approximately...
- Chromosome
- A discrete, condensed structure consisting of a single long DNA molecule complexed with histone proteins. Humans normally carry 46 chromosomes in 23...
- CODIS
- The FBI's Combined DNA Index System, the US national STR-based forensic DNA database. Contains profiles from convicted offenders, arrestees, and unidentified crime-scene...
- ESS (European Standard Set)
- The set of STR loci required for profiles entered into EU national databases participating in Prüm cross-border DNA exchange. Currently aligned with...
- 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...
- Locus (Plural: Loci)
- A defined physical position on a chromosome. In forensic genetics, 'locus' usually refers to a specific STR site used in profiling. The...
- 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...
- STR (Short Tandem Repeat)
- A genomic locus where a 2, 7 base-pair unit is repeated in tandem a variable number of times between individuals. The variation...
- VNTR (Variable Number Tandem Repeat)
- A tandemly repeated genomic sequence with a longer repeat unit (typically 10, 60 bp) than an STR. VNTRs were used in the...
Explained in these topics
- Chromosomes, Genes and the Human GenomeThe proportion of individuals in a population who carry two different alleles at a locus. A locus with high heterozygosity is more informative for forensic pro...
- Polymorphism, Heredity and the Markers that Identify a PersonThe probability that two alleles chosen at random from a population at a given locus are different. A locus with heterozygosity approaching 1.0 is maximally in...