Gene
Definition
A segment of DNA that encodes a functional product, most commonly a protein but also non-coding RNA molecules. Protein-coding genes occupy roughly 1.5 percent of the human genome sequence; the rest is non-coding.
- Definition
- DNA segment encoding a functional product
- Common product
- Protein, also non-coding RNA
- Genome share
- Protein-coding genes occupy about 1.5% of the human genome
Common questions
If protein-coding genes are only 1.5 percent of the genome, what does forensic DNA profiling actually target?+
Standard forensic STR profiling targets non-coding, highly variable repeat regions rather than genes themselves, precisely because these regions carry no functional or health information and simply provide a highly individualising identification marker.
Why does the small proportion of coding DNA matter to privacy debates around forensic DNA databases?+
Because forensic STR loci sit outside coding gene regions, they generally do not reveal health conditions or trait information, which is a key argument used to distinguish forensic identification profiling from full genomic sequencing on privacy grounds, though this distinction has limits as genealogy databases use broader genomic data.
How does a gene differ from an allele in forensic genetics?+
A gene is the DNA segment or locus itself, while an allele is one of the alternative sequence variants that can occur at that locus in different individuals; forensic profiling compares which alleles a person carries at a chosen set of loci, not the genes' functional products.
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...
- Heterozygosity
- The proportion of individuals in a population who carry two different alleles at a locus. A locus with high heterozygosity is more...
- 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...