Also known as:deoxyribonucleic acid · genetic evidence · DNA profiling
Written by attorneys · grounded in primary & secondary sources — see below
An identification technique based on analysis of an individual's unique genetic material. The resulting profile permits comparison of biological samples to determine the source with a high degree of statistical certainty when properly generated and interpreted by a qualified expert.
Sources & Authorities
How it applies
Common Examples
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Expert Comparison of DNA Profiles
After a sexual assault, police obtain a vaginal swab from the victim and a blood sample from suspect Diego Duarte. State analyst Dr. Lopez generates a profile from Duarte's sample and compares it to a profile produced by a private lab from the swab. At trial Dr. Lopez testifies that the profiles match and offers her own opinion on the comparison. The court admits the testimony because the private-lab profile serves only as underlying data for the expert's independent conclusion.
DNA Reliability Hearing
Plaintiff Deborah Dunn alleges that a prescription drug caused her child's birth defect. Defendant Dover Bank moves to exclude the plaintiff's expert who relies on DNA linkage studies to show causation. The court conducts a pretrial hearing to assess whether the DNA methodology is scientifically valid and whether the expert's application of it is reliable before deciding admissibility.
Select any source to read its text and confirm it supports the definition.
Cases
Federal Rules
Restatements
Casebooks
Hornbooks
Course Outlines
Study Supplements
Daubert v. Merrell Dow Pharmaceuticals, Inc.509 U.S. 579, 592 (1993)
DNA Sample Destruction Claim
Defendant Damian Decker is convicted of robbery. After conviction he seeks post-conviction DNA testing of semen evidence that the state destroyed. Decker claims the destruction violated due process. The court denies relief, holding that a convicted offender has no freestanding federal right to post-conviction DNA testing where state procedures are not fundamentally unfair.
DNA-Based Paternity Order
Immigration authorities seek to deport Tuan Ahn Nguyen. His father obtains a state-court parentage order based on DNA testing that establishes biological paternity. Nguyen argues the order satisfies statutory requirements for derivative citizenship. The court examines whether the DNA evidence and resulting order meet the criteria for establishing the parent-child relationship under immigration law.
Tuan Ahn Nguyen v. Immigration and Naturalization Service533 U.S. 53, 74 (2001)
DNA Booking After Arrest
Police arrest Doris Duffy for a serious felony and transport her to the station. As part of routine booking they swab the inside of her cheek for DNA and enter the profile into a database. Duffy later moves to suppress the resulting match to an unsolved crime. The court upholds the swab as a reasonable booking search incident to lawful detention.
DNA Evidence in Capital Case
Defendant Dwight Dorsey is convicted of raping and murdering a child. The prosecution introduces DNA evidence linking Dorsey to the crime scene. On appeal Dorsey argues that the death penalty for this offense violates the Eighth Amendment. The court considers whether the presence of DNA proof affects the constitutionality of capital punishment for the crime.
Kennedy v. Louisiana554 U.S. 407, 128 S.Ct. 2641, 171 L.Ed.2d 525 (2008)
Common questions
Frequently Asked
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When may an expert testify about a DNA profile generated by a non-testifying laboratory?+
An expert may testify about such a profile when the profile is used only as the basis for the expert's own independent opinion and is not offered for its truth. The expert must be subject to cross-examination about the methods, assumptions, and reliability of the comparison.
Supporting sources
Is collection of a cheek swab for DNA analysis during booking a reasonable search?+
Yes. When officers arrest a suspect for a serious offense and bring the person to the station for detention, taking and analyzing a cheek swab as part of routine booking constitutes a reasonable search under the Fourth Amendment.
Supporting sources
How is DNA evidence used to prove parentage in intestate succession?+
DNA analysis may establish biological paternity or maternity. Once the genetic link is shown, the claimant must still satisfy any additional statutory requirements for recognition as a surviving descendant entitled to take by representation.
Supporting sources
509 U.S. 579, 592 (1993)Evidence
…might be, id. at ----, 113 S.Ct. at 2797. [^maj-5]: There are, of course, exceptions. Fingerprint analysis, voice recognition, DNA fingerprinting and a variety of other scientific endeavors closely tied to law enforcement may indeed have the courtroom as a principal theatre of operations. See, e.g., United States v.…