Amelogenin Gene A genetic locus useful for determining gender.
Amino Acids The building blocks of proteins. There are twenty common amino acids. Amino acids are linked to form a protein. The types of amino acids and the order in which they’re linked determine the character of each protein.
Buccal Cells Cells derived from the inner cheek lining.
Chromosome A rodlike structure in the cell nucleus, along which the genes are located. It is composed of DNA surrounded by other material, mainly proteins.
Complementary Base Pairing The specific pairing of base A with T and base C with G in double-stranded DNA.
DNA Abbreviation for deoxyribonucleic acid—the molecules carrying the body’s genetic information. DNA is double stranded in the shape of a double helix.
Electrophoresis A technique for separating of molecules through their migration on a support medium while under the influence of an electrical potential.
Epithelial Cells The outer layer of skin cells. These DNA-bearing cells often fall off or are rubbed off onto objects retrieved from crime scenes.
Human Genome The total DNA content found within the nucleus of a cell. In humans, it is composed of approximately three billion base pairs of genetic information.
Hybridization The process of joining two complementary strands of DNA to form a double-stranded molecule.
Low Copy Number Fewer than eighteen DNA-bearing cells.
Mitochondria Small structures located outside the nucleus of a cell. These structures supply energy to the cell. Maternally inherited DNA is found in each mitochondrion.
Multiplexing A technique that simultaneously detects more than one DNA marker in a single analysis.
Nucleotide The unit of DNA consisting of one of four bases—adenine, guanine, cytosine, or thymine—attached to a phosphate-sugar group.
Picogram One-trillionth of a gram, or 0.000000000001 gram.
Polymer A substance composed of a large number of atoms. These atoms are usually arranged in repeating units, or monomers.
Polymerase Chain Reaction (PCR) A technique for replicating or copying a portion of a DNA strand outside a living cell. This technique leads to millions of copies of the DNA strand.
Primer A short strand of DNA used to target a region of DNA for replication by PCR.
Proteins Polymers of amino acids that play basic roles in the structures and functions of living things.
Replication The synthesis of new DNA from existing DNA.
Restriction Enzymes Chemicals that act as scissors to cut DNA molecules at specific locations.
Restriction Fragment Length Polymorphisms (RFLP) Different fragment lengths of base pairs that result from cutting a DNA molecule with restriction enzymes.
Sequencing A procedure used to determine the order of the base pairs that constitute DNA.
Short Tandem Repeat (STR) A region of a DNA molecule that contains short segments consisting of three to seven repeating base pairs.
Substrate Control An unstained object adjacent to an area on which biological material has been deposited.
Tandem Repeat A region of a chromosome that contains multiple copies of a core DNA sequence that are arranged in a repeating fashion.
Y-STRs Short tandem repeats located on the human Y chromosome. Their utility in forensic science is that they originate only from a male donor of DNA.