Document Category: DNA

This motion relies on the Federal Rules of Evidence to argue for exclusion of expert DNA testimony about the likelihood ratio obtained using STRMix probabilistic genotyping software. Pages 5-8 describe the basic steps of DNA extraction and analysis. Pages 8-9 discuss the problems of trace DNA and the possibility of innocent transfer of DNA.  Page 11 explains how DNA analysis is less reliable when there is a complex DNA mixture and pages 12-15 discuss the danger that jurors will misunderstand (and prosecutors will misrepresent) what a likelihood ratio actually means.

This brief argues that law enforcement’s warrantless upload of a suspect’s SNP profile to GEDmatch and subsequent genealogical investigation violated the Alaska and federal constitutions. The brief explains how SNP-based genetic genealogy reveals highly information-rich data—including intimate familial associations and biological characteristics—far beyond traditional STR identity testing. It contends that both the suspect and his relatives retain a reasonable expectation of privacy in their shared genetic segments and that the third-party doctrine does not permit unregulated access to such sensitive data. Relying on Katz, Carpenter, and Alaska’s broader constitutional privacy protections, the brief argues that this novel surveillance technique constitutes a search requiring a warrant.

Explains the issue of secondary DNA transfer – footnotes on p. 7 specifically cite studies demonstrating a person’s DNA can be transferred to an object they never touched via an intermediate person or object.

Amicus brief from the Innocence Project explains genotyping software, similar software programs used in courts that were shown to be unreliable, and why defense access to the software source code is necessary.

This amicus brief from the Legal Aid Society explains how probabilistic genotyping software works, why it’s unreliable, and why the defense has to be granted access to the software’s source code to present a full defense

Argues that “likelihood ratio” evidence — the statistical frequency of a suspect’s characteristic — has not been sufficiently validated and is misleading to the jury because the jury conflates it with probability of guilt.