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Name: People v. Stevey
Case #: C062760
Court: CA Court of Appeal
District 3 DCA
Opinion Date: 09/18/2012
Summary

The Y-STR procedure for DNA analysis and to generate probabilities is not a new scientific technique that necessitates a Kelly hearing. Appellant was convicted of various sex crimes. During trial, the court denied the defense request to conduct a Kelly prong-one hearing to determine whether the Y-STR testing and the methodology to interpret the results on mixed samples were generally accepted in the scientific community. “Reliability” under Kelly means that the method must have gained general acceptance in the relevant scientific community. Y-STR testing was developed to isolate male DNA in a mixed sample; all males in a paternal lineage will possess the same Y-STR DNA profile. While Y-STR testing has limitations in positively identifying an individual, it is useful to exclude individuals in a mixed sample. The fact that Y-STR testing cannot positively identify an individual does not mean the test is unreliable or a new scientific method—it is a refinement of STR DNA testing whose probative value is a question of the weight of the evidence, not its admissibility. It has been generally accepted in the relevant scientific community.

The protocol for use of RFU (relative florescent units) levels to interpret PCR/STR DNA test results need not be nationally standardized. A criminalist testified regarding the results of DNA testing on a saliva sample, using the PCR/STR procedure. Appellant argued that the interpretation of those results should have been subjected to a Kelly prong-one hearing because the use of RFU levels is not nationally standardized. He argued that the laboratory’s high RFU threshold may have excluded exonerating evidence. The “fact that some laboratories interpret results more conservatively than others does not indicate the absence of general acceptance of a scientific technique.”