Forensics

How does forensic identification work?

Any type of organism can be identified by examination of DNA sequences unique to that species. Identifying individuals within a species is less precise at this time, although when DNA sequencing technologies progress farther, direct comparison of very large DNA segments, and possibly even whole genomes, will become feasible and practical and will allow precise individual identification.

To identify individuals, forensic scientists scan 13 DNA regions that vary from person to person and use the data to create a DNA profile of that individual (sometimes called a DNA fingerprint). There is an extremely small chance that another person has the same DNA profile for a particular set of regions.

Some Examples of DNA Uses for Forensic Identification

Identify potential suspects whose DNA may match evidence left at crime scenes

Exonerate persons wrongly accused of crimes

Identify crime and catastrophe victims

Establish paternity and other family relationships

Identify endangered and protected species as an aid to wildlife officials (could be used for prosecuting poachers)

Detect bacteria and other organisms that may pollute air, water, soil, and food

Match organ donors with recipients in transplant programs

Determine pedigree for seed or livestock breeds

Authenticate consumables such as caviar and wine

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Is DNA effective in identifying persons?

[answer provided by Daniel Drell of the U.S. DOE Human Genome Program]

DNA identification can be quite effective if used intelligently. Portions of the DNA sequence that vary the most among humans must be used; also, portions must be large enough to overcome the fact that human mating is not absolutely random.

Consider the scenario