Default Judgement: A decision made by the court or administrative authority when the defendant fails to respond or appear, i.e., defaults.

Degradation: The breaking down of DNA by biological or chemical processes. In the context of forensic science these processes are usually the result of cell death or exposure to the elements.

Diploid: Containing a complete set (one from each parent) of homologous (similar) chromosomes.

Direct Exclusion: When a characteristic is found in the child that is not in the child's mother, it must have come from the biological father. If an alleged father does not have the factor, he is excluded for that system. If an alleged father is excluded on two independent tests, he is excluded as the biological father of the child.

Discovery; Pretrial Discovery: Discovery is the formal procedure for gathering information pursuant to rules of court.

DNA (Deoxyribonucleic Acid): The molecule that encodes genetic information. DNA is a double-stranded helix held together by weak bonds between base pairs of nucleotides. DNA is a genetic material that is routinely tested in parentage evaluations.

DNA Polymerase: An enzyme that produces or synthesizes DNA. These enzymes always use an existing DNA molecule as a template for producing a new strand of DNA.

DNA Probe: A short piece of DNA made in the laboratory by chemical or biological means that can be labeled with a tracer and used to identify a specific gene. A specific gene is identified by a specific DNA probe.

DNA Profiling or Typing: A variety of DNA tests used by forensic scientists to aid in the identification of the individual source of evidence or to resolve a parentage question.

Dominant: When on allele's expression in an individual masks the expression of another allele in that individual. Example: people with type A blood can either have two A alleles or one A allele and one O allele. The O allele will not be seen due to the presence of the dominant A allele (see recessive and codominant).

Double Helix: The structure of DNA. Two strands of DNA coiled around each other forming a spiral staircase like structure.