Chromosome

Related terms

Autosomal vs Mitochondrial DNA

Autosomal DNA is nuclear, biparentally inherited, present as two copies per cell. Mitochondrial DNA is cytoplasmic, maternally inherited, present in hundreds to...

Capillary Electrophoresis

Size separation of fluorescently labelled PCR products through a polymer-filled capillary on an instrument like the ABI 3500. Output is an electropherogram.

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...

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...

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...

Multiplex STR Kit

Single-tube PCR amplifying 15+ STR loci plus amelogenin in one reaction. AmpFISTR Identifiler Plus and PowerPlex are the workhorses in Indian DNA...

Nucleotide

The monomer unit of nucleic acids. Each nucleotide consists of a five-carbon sugar (deoxyribose in DNA, ribose in RNA), a phosphate group,...

PCR

Polymerase Chain Reaction. Kary Mullis 1983. Exponential amplification of a target sequence using a thermostable Taq polymerase, two primers and thermal cycling.

Polymorphism

The existence of two or more sequence variants (alleles) at a locus in a population at a frequency above one percent. High...

RFLP

Restriction Fragment Length Polymorphism. The first-generation DNA typing method using restriction enzymes and Southern blotting. Required nanograms of intact DNA.

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 these topics

• Chromosomes, Genes and the Human GenomeA discrete, condensed structure consisting of a single long DNA molecule complexed with histone proteins. Humans normally carry 46 chromosomes in 23 homologous...
• DNA in Forensic Science: Structure, Genetic Markers, Extraction and ProfilingPackaged DNA. Humans have 22 pairs of autosomes plus one pair of sex chromosomes (XX or XY), all housed in the nucleus, plus a small circular mitochondrial gen...