The People v. Brown
| Decision Date | 14 August 2001 |
| Citation | 110 Cal.Rptr.2d 750,91 Cal.App.4th 623 |
| Court | California Court of Appeals Court of Appeals |
| Parties | (Cal.App. 5 Dist. 2001) THE PEOPLE, Plaintiff and Respondent, v. FREDERICK RAY BROWN, Defendant and Appellant. F034208 FIFTH APPELLATE DISTRICT Filed |
APPEAL from a judgment of the Superior Court of Kern County. Kenneth C. Twisselman II, Judge.
David Joseph Macher, under appointment by the Court of Appeal, for Defendant and Appellant.
Bill Lockyer, Attorney General, David P. Druliner, Chief Assistant Attorney General, Robert R. Anderson, Assistant Attorney General, W. Scott Thorpe and David A. Rhodes, Deputy Attorneys General, for Plaintiff and Respondent.
CERTIFIED FOR PARTIAL PUBLICATION*
O P I N I O N
The jury found defendant and appellant Frederick Brown guilty of forcible rape (Pen. Code, 261, subd. (a)(2); count 1)1 and incest ( 285; count 2). The trial court found true the special allegations that Brown had suffered two prior serious felony convictions within the meaning of section 667, subdivision (a), and the Three Strikes law ( 1170.12), and had served five prior prison terms ( 667.5, subd. (b)). Brown was sentenced to 38 years to life in prison.
We affirm the judgment. For no purpose other than to expand the universe of reported decisions which deal with DNA2 evidence, we publish the portion of this opinion which addresses Brown's contention the trial court erred by admitting DNA evidence because (a) the database used to calculate the probability of his genetic profile was for various reasons inadequate, and (b) the prosecution failed to call one of the DNA analysts to testify as to her testing procedures.
Brown contends the trial court committed reversible error by admitting DNA evidence which established he could not be excluded as a source of the perpetrator's DNA.3 He raises his contentions under the third prong of People v. Kelly (1976) 17 Cal.3d 24, in which the Supreme Court articulated this three-step test for the admission of evidence generated by a new scientific technique: (1) the reliability of the technique must be sufficiently established to have gained general acceptance in the relevant scientific community; (2) the witness providing the evidence must be properly qualified as an expert; and (3) the evidence must establish that, in the particular case, the correct and accepted scientific technique was actually followed. (People v. Kelly, supra, 17 Cal.3d at p. 30; People v. Soto (1999) 21 Cal.4th 512, 518-519; People v. Venegas (1998) 18 Cal.4th 47, 81.)
Brown stipulated at trial to the scientific acceptance of the PCR (polymerase chain reaction) techniques used in this case, the first Kelly prong,4 and he has not challenged the finding that his DNA profile matched that of the perpetrator. However, he contends use of the Cellmark African American database and calculations of genotypic frequencies derived from that database did not amount to correct and accepted procedure under Kelly's third prong. Specifically, he claims the database was inadequate because (1) it was not in Hardy-Weinberg equilibrium; (2) it was not in linkage equilibrium; (3) it was subject to population substructure because the samples were not randomly selected; and (4) it was too small. Brown also contends, again under the third Kelly prong, that the prosecution failed to establish the DNA analysis itself was conducted in a proper and acceptable manner because only one of the two Cellmark DNA scientists who performed the analysis was called to testify, thereby precluding determination of whether the other analyst followed the proper procedures, and violating Brown's Sixth Amendment right to confront his accuser.
We begin with some simplified biology. The genetics of a human cell can be compared to a library, the genome, composed of 46 books, each a single chromosome. The text contained in the books is written in DNA, the chemical language of genetics. The library is compiled by the owner's parents, each of whom contributes 23 books, which are then matched up and arranged together in 23 paired sets inside the sacrosanct edifice of the nucleus. During embryonic development, the original library is copied millions of times so that each cell in the human body contains a copy of the entire library.5
Twenty-two of the twenty-three paired sets of books are entitled "Chromosome 1" through "Chromosome 22"; externally, the two paired books of each set appear to be identical in size and shape. However, the twenty-third set, which contains information on gender, consists of one book entitled "Chromosome X" (given by the mother) and one book entitled either "Chromosome X" or "Chromosome Y" (given by the father and determining the sex of the library's owner). The 22 sets comprising "Chromosome 1" through "Chromosome 22" address an enormous variety of topics describing the composition, appearance, and function of the owner's body. In addition, they include a considerable amount of what appears to be nonsense. The two paired books of each set, one book from each parent, address identical topics, but may contain slightly different information on those topics. Thus, two paired books opened to the same page contain corresponding paragraphs, but the text within those corresponding paragraphs may vary between the two books. For example, within the paragraph addressing eye color, one book may describe blue eyes while the other book of the set may describe brown eyes.6
The two corresponding, but potentially variant, paragraphs in the two paired books are called alleles. If, for a particular topic (i.e., at a particular region or locus on the DNA), the allele from the mother is A and the corresponding allele from the father is B, the genotype at that locus is designated AB. The text of two corresponding alleles at any locus may be identical (a homozygous genotype, e.g., AA) or different (a heterozygous genotype, e.g., AB). Regardless, one person's genetic text is, in general, extremely similar to another person's; indeed, viewed in its vast entirety, the genetic text of one human library is 99.9 percent identical to all others. As a result, the text of most corresponding paragraphs varies only slightly among members of the population.
Certain alleles, however, have been found to contain highly variable text. For example, alleles are composed of highly variable text when they describe structures requiring enormous variability. Also, some alleles appear to contain gibberish that varies greatly, or repeated strings of text that vary not in text but in repeat number. These variants (polymorphisms) found at certain loci render each person's library unique7 and provide forensic scientists a method of differentiating between libraries (people) through the use of forensic techniques that rely on the large number of variant alleles possible at each variable locus. For example, the combined libraries of the human population may contain two variant alleles at a particular locus, three at another, nine at another, and so on. Since each person receives two alleles for each locus, the number of possible combinations is further increased.
When a sample of DNAusually in the form of hair, blood, saliva, or semenis left at the crime scene by a perpetrator, a forensic genetic analysis is conducted. First, DNA analysts create a genetic "profile" or "type" of the perpetrator's DNA by determining which variants or alleles exist at several variable loci. Second, the defendant's DNA is analyzed in exactly the same manner to create a profile for comparison with the perpetrator's profile. If the defendant's DNA produces a different profile than the perpetrator's, even by only one allele, the defendant could not have been the source of the crime scene DNA, and he or she is absolutely exonerated.8 If, on the other hand, the defendant's DNA produces exactly the same genetic profile, the defendant could have been the source of the perpetrator's DNAbut so could any other person with the same genetic profile. Third, when the perpetrator's and defendant's profiles are found to match, the statistical significance of the match must be explained in terms of the rarity or commonness of that profile within a particular populationthat is, the number of people within a population expected to possess that particular genetic profile, or, put another way, the probability that a randomly chosen person in that population possesses that particular genetic profile.9 Only then can the jury weigh the value of the profile match. (People v. Venegas, supra, 18 Cal.4th at p. 82.)10.
Performing this last step-the determination of the profile's rarity-requires information about the relevant population. For example, if the victim reports that the perpetrator had blue eyes and abnormally short fingers (brachydactyly), forensic scientists will need to know how rare the combination of blue eyes and brachydactyly is in the population. That determination requires knowledge of the separate frequencies of these two traits in the populationhow many people have blue eyes and how many people have brachydactyly. But it is impractical to actually examine the entire population to count every person with blue eyes and every person with brachydactyly; instead, scientists create a database of randomly selected people, and use the frequencies of the traits of that group of people to represent the entire population. If among the people used to compile the database the occurrence of blue eyes is fairly common and the occurrence of brachydactyly is very uncommon, then the probability of the two traits occurring together will be extremely rare. That determination, derived from the database, is presumed to apply to the entire population the database was created to represent. Therefore, the reasoning goes, if very few people are expected to have both traitsthat is, if the profile is rarethe...
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