Opinion ID: 1160857
Heading Depth: 1
Heading Rank: 5

Heading: Kelly Hearing in the Municipal Court

Text: At the preliminary examination, Robert Keister, the criminalist in charge of RFLP analysis at the OCSD crime laboratory, testified that RFLP analysis of DNA samples from defendant's blood and from a semen stain on the seized bedspread showed matches at four DNA loci. As previously indicated, he calculated there was a probability of 1 in 189 million of finding that same DNA pattern in individuals selected at random from the population represented by the OCSD's Hispanic database. [19] The principal issue at the preliminary examination was the admissibility of the DNA evidence under Kelly, supra, 17 Cal.3d 24, 130 Cal.Rptr. 144, 549 P.2d 1240. Defendant stipulated to general scientific acceptance of the OCSD crime laboratory's RFLP procedures up through production of the autorads from which the sizes of the DNA samples (alleles) were measured. During the 11 days of Kelly hearing testimony, held from July 30 to November 15, 1991, the parties elicited extensive DNA testimony from 3 prosecution experts: the criminalist, Robert Keister, and two human population geneticists, Ranajit Chakraborty and Bruce Kovacs. Each testified to the reliability of the product rule in frequency determinations involving human populations, and to the validity of the work, both analytical and mathematical, performed by the OCSD laboratory. Both sides also introduced voluminous exhibits. The defense called no witnesses at the Kelly hearing in the municipal court. Dr. Chakraborty, a recognized authority in human population genetics involving RFLP, [20] was routinely asked by DNA laboratories around the country to review their work and validate their databases used for generating probability statistics in RFLP analysis of DNA profiles. In his opinion the OCSD crime laboratory was the most careful in terms of validating its databases. He testified that application of the unmodified product rule was proper in the OCSD crime laboratory's analyses of probability estimatesall of the assumptions justifying use of the rule were supported by the laboratory's databases, including both Hardy-Weinberg equilibrium (independence of alleles at a locus) and linkage equilibrium (independence of probes across multiple loci). Dr. Chakraborty used a series of tests to review and examine the DNA databases, calculations and extrapolations, taking particular note of criticisms by Drs. Lewontin and Hartl, who, along with Dr. Laurence Mueller and Eric Lander, had questioned using the product rule because of fears that population substructuring might negatively affect the accuracy of such applications. The OCSD crime laboratory had sent a computer diskette of its entire database, involving DNA profiles from over 1,200 persons, to Dr. Chakraborty for analysis and verification of its validity. Using computer programs, he concluded the unmodified product rule could be reliably applied in calculating probability estimates from such data. [21] Dr. Chakraborty also testified that the OCSD crime laboratory's fixed-bin method of calculating a probability estimate (similar to that used by the FBI laboratory) was conservative. Several characteristics of the method guard against underestimation, and often lead to overestimation favorable to the defendant, of the actual allele frequencies. The fixed bins are generally much wider than the actual ability of the laboratory to distinguish between alleles. The bins are collapsed into larger bins until each bin has a minimum of five occurrences. For apparent single-banded patterns, a conservative 2p frequency calculation is used (p being the probability of the occurrence of a single band at a given locus) instead of the p-squared standard Hardy-Weinberg calculation. And if an allele falls close to a bin boundary, the higher probability of the two adjacent bins is used in calculating a probability estimate. Dr. Bruce Kovacs was a professor at the University of Southern California School of Medicine. He was involved in genetic research relevant to specific human DNA mutations both at the University of Southern California and in the Department of Medical Genetics at the City of Hope Medical Center. [22] He was also an investigator for the human genome mapping project and had been a peer reviewer for the American Journal of Human Genetics and several other scientific journals. Kovacs testified he examined the OCSD crime laboratory's work in this case and concluded the laboratory's RFLP analysis, use of the product rule, and calculation of probability frequencies would all be generally accepted in the human population genetics community. Specifically, that scientific community would accept the initial 1-in-214-million probability estimate (see ante, fn. 19 at 88 Cal.Rptr.2d at p. 44, 981 P.2d at p. 967) for Soto's 4-probe banding profile, based on the Orange County Hispanic database, as reliable. At the conclusion of the preliminary examination, the magistrate ruled that RFLP methodology for forensic DNA analysis is generally accepted by the relevant scientific community, that the methodology was correctly followed in this case by the OCSD crime laboratory, and that therefore Keister's testimony of the very small probability of a random match with the DNA found in defendant's blood and in the semen stain would be admissible in evidence. Accordingly, defendant was ordered held to answer in superior court.