Glossary

Agarose gel
A gelatin-like substance used as a medium in biochemistry and biotechnology applications through which large molecules are sorted by size and/or charge.
Allele
Any alternative form of a DNA sequence at any locus (specific region of a chromosome), including a gene, a regulatory sequence, or segment of non-coding and non-regulatory DNA.
Amplify
To repeatedly copy a molecule such as DNA, usually until there are billions of copies present.
Base pairs
Pairs of complementary nucleotides, G–C, A–T; unit of length for a DNA fragment.
CITES
Convention on International Trade in Endangered Species of Wild Fauna and Flora. CITES is an international agreement (first proposed in 1963 and ratified by the United States in 1973) among 182 member parties to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Elephant poaching is prohibited by CITES.
DNA analysis
Process of amplifying, sequencing, and/or sorting DNA fragments, and in some instances, entire genomes.
DNA fingerprint
Collection of DNA fragments that can be used to identify genetically unique individuals; also known as a DNA profile, genetic fingerprint, or genetic profile.
DNA ladder
A set of DNA fragments of known lengths that are used to determine the lengths of other fragments when samples are analyzed using gel electrophoresis.
DNA profile
Collection of DNA fragments that can be used to identify genetically unique individuals; also known as a DNA fingerprint, genetic profile, or genetic fingerprint.
Dung
Excrement (poop) from an animal such as an elephant; contains cells from the animal that can provide DNA samples.
Federal regulations
Rules and laws that apply to a nation. The primary federal regulation in the United States that covers ivory trade is the Endangered Species Act (ESA). In June 2016, the U.S. Fish and Wildlife Service instituted a near-total ban on the domestic commercial trade of African elephant ivory. The rule, which fulfills restrictions outlined under President Obama's 2013 Executive Order on Combating Wildlife Trafficking, substantially limits imports, exports and sales of African elephant ivory across state lines.
Flanking sequence
Region of DNA on either side of a sequence of interest, such as an STR or gene.
Forensics
Scientific tests and techniques used in connection with a criminal case, such as illegal poaching.
Forest elephants
Group of African elephant native to densely wooded rainforests of west and central Africa. Forest elephants are considered a separate species (Loxodonta cyclotis) by many researchers, including Sam Wasser, but are listed as a subspecies in The IUCN Red List of Threatened Species. Forest elephants are smaller than savanna elephants with smaller, more oval-shaped ears and straighter downward slanting tusks.
Frequency
How often something occurs. For alleles, frequency indicates the number of times an allele at a particular locus is found in a population compared to the total number of times alleles for that locus are counted in the population.
Gel electrophoresis
A technique by which DNA fragments are separated by size. It uses an electrical voltage applied to one end of an agarose gel plate; smaller fragments migrate more quickly through the gel.
Genetic profile
Collection of DNA fragments that can be used to identify genetically unique individuals; also known as a DNA fingerprint, DNA profile, or genetic fingerprint.
Genetic fingerprint
Collection of DNA fragments that can be used to identify genetically unique individuals; also known as a DNA fingerprint, DNA profile, or genetic profile.
Homozygous
Having two identical alleles at a given locus.
Heterozygous
Having two different alleles at a given locus.
Locus (pl: Loci)
A particular location on a chromosome in the genome of an organism.
Marker
Markers refer to the flanking areas at a particular locus, allowing the STRs at that locus to be isolated and amplified by PCR.
Mitochondrial DNA
Mitochondrial DNA is the small circular chromosome found inside mitochondria. Unlike nuclear DNA, mitochondrial DNA is passed from mother to offspring.
Noncoding
Portion of the genome that does not direct the production of a polypeptide
Nuclear DNA
Found in the nucleus, the membrane-bound organelle that contains the cell's chromosomes.
Nucleotide
Basic structural unit of nucleic acids (DNA and RNA); consists of a phosphate group, nitrogen-containing base (adenine, cytosine, guanine, thymine [DNA only], uracil [RNA only]), and pentose sugar (ribose for RNA, deoxyribose for DNA).
Polymerase chain reaction (PCR)
A laboratory technique used to amplify DNA sequences to produce billions of copies of an individual fragment of DNA. The method involves using short DNA segments, or primers, to select the sections of the genome to be amplified.
Savanna elephants
Group of African elephants native to the grassy plains of eastern and southern Africa; considered a separate species (Loxodonta africana) by some researchers, including Sam Wasser, but it is listed as a subspecies in The IUCN Red List of Threatened Species. Savanna elephants are larger than forest elephants with larger ears and outward curving tusks.
Short tandem repeat (STR)
Highly variable segments of DNA, typically of noncoding and nonregulatory DNA, that occur throughout the genome and contain repeats of the same sequence of several nucleotides lined up, one after the other (for example, CTACTACTACTA).
State laws
Rules and laws that apply to a particular US state. As of June 2016, California, New York, and New Jersey have passed state laws that prohibit nearly all commerce involving elephant ivory.
Statistical methods
Procedures for collecting and analyzing data sets. Sam Wasser and his team uses statistical methods to match DNA profiles from seized ivory to a population-specific reference map of genetic profiles of wild elephant herds across Africa.
Well
In gel electrophoresis, a small trough in an agarose gel into which a DNA sample is placed or "loaded" prior to starting the electrical current.