Laboratory Definitions

These are the numbered types of chromosomes that carry genes that are not sex related; in humans there are 23 chromosomes with chromosomes 1-22 being autosomes and the last pair being a letter coded pair to determine the biological sex, this is called the pair of sex chromosomes.

Fluids or any secretions produced and deposited/transferred by an individual; examples include saliva, blood, semen, sweat, urine, etc..

When the cell is not in an active state of division the DNA exists in a long, non-compacted/coiled form but when the cell enters a division cycle the DNA gets condensed and coiled into structures called chromosomes inside the nucleus to allow with proper division of the genetic material during cell division.

Genetic material that is present in almost all cells of the body (not including mature red blood cells, skin cells, hair cells, and nails) that consists of the biological blueprint of the individual’s genetic makeup.

A genetic methodology followed to identify the victims of mass disasters by collecting evidence from the scene, generating DNA profiles and comparing the reference samples gathered by people known/suspected of being there; for instance, in the case of a plane crash leading to fatality of passengers, the DNA profiles generated from the evidence/remains at the scene would be compared to DNA profiles of reference samples gathered from the known list of passengers and employees on the flight.

The process that DNA samples are treated with in order to extract, recover, and characterize the genetic makeup from a DNA sample.

• DNA extraction: chemical processes performed on the evidentiary sample that allow for the DNA to be removed from the nucleus of the cells and separated from other cellular material and debris. The solution presumed to contain the DNA is extracted for further analysis.
• Quantification: a step in the DNA analysis where the concentration of the DNA is determined to ensure that there is enough DNA to profile.
• Amplification: once enough DNA is collected this process allows the duplication of the DNA sample by mimicking DNA replication in a cell; this is done by providing the biological machinery necessary for DNA replication.
• Genotyping: the final step in taking the amplified DNA and determining the DNA profile.

A report produced after analyzing a biological sample, that presents the genetic makeup as genotypes of the individual at specific sites along the DNA known as genomic markers.

The analytical procedure that is followed to process a DNA sample and produce a DNA profile of specific regions of the human genome.

A study that traces lineages through generations of a family using several different types of data which may include genetic data; may be used as an investigative tool in cold cases such as the Golden State killer and the recent Murder of Christine Jessop case.

The biological process of cell division and fertilization allows the genetic information of the parents to be passed onto their offspring carrying their genetic traits and characteristics from one generation to the next.

The complete set of genes or genetic material found in the cells of an organism.

A subset of forensic biology where biological materials are studied and analyzed for attribution purposes in cases where there is suspected bioterrorism, the use of biological toxins/agents in a criminal or terrorist associated activity.

An organelle in the cell responsible for conducting metabolic processes to generate enough energy for the cell to function.

A field of study where the genetic makeup of an individual and their response to specific drugs given during drug therapy are studied to determine how genetics play a role in the efficacy of a drug in an individual.

A type of screening technique employed to determine the type specimen present on the evidence at hand to determine the confirmatory analysis to apply; a methodology carried out when the case history indicates possibility of bodily fluid deposits/transfers on the evidence in question . For instance, if the case history indicates a possible sexual assault the victim’s clothing may be tested for the presence of sperm cells using a presumptive test and if confirmed further testing in the localized section where the sperm were located will be carried out.

Sample collected from a known origin and compared to the forensic evidence containing DNA profile of unknown origin or other DNA profiles in the case/database.

A method of analysis used to presumptively identify the specimen type under analysis allowing analyst to take a more directed approach of analysis for confirmation or further testing; may include a physical examination and/or presumptive tests examining presence of specific antigens/bodily fluids.

A field within forensic sciences that identifies, characterizes, and analyzes bodily fluids such as blood, saliva, semen, sweat, etc.

Units of repeated genetic code in the DNA that consist of 3 or more nucleotides (letter codes) that are easy to analyze and compare between different samples. The number of repeats within specific genetic markers are used as the numerical allocations for the allele number for that specific marker; this ultimately yields a DNA profile as many different markers are used.

Chromosomes that determine the sex of the organism and carry specific genes that are linked to the chromosomes.