Opinion ID: 1154894
Heading Depth: 3
Heading Rank: 1

Heading: The background of DNA testing

Text: Arresting officers noticed blood on Defendant's shirt. During the next few months, Cellmark Diagnostic Laboratories, Inc. (Cellmark) performed DNA testing on this blood as well as the victim's bone and muscle samples. Test results showed a match between the DNA in the blood on Defendant's shirt and the DNA in the victim's muscle sample. Further testing in 1990 showed that the DNA in the blood on the shirt did not match Defendant's DNA. The State moved for a Frye hearing to determine the admissibility of the DNA test results. See United States v. Frye, 293 F. 1013 (D.C. Cir.1923). After an extensive hearing, the trial court found that the DNA testing performed was generally accepted in the relevant scientific community and admitted the results at trial. Defendant challenges this finding. For criminal cases, DNA testing is a very recent advent. In October 1988, an appellate court first considered the admissibility of DNA testing in the criminal context. See William C. Thompson & Simon Ford, DNA Typing: Acceptance and Weight of the New Genetic Identification Tests, 75 Va.L.Rev. 45, 46 n. 4 (1989) (Thompson & Ford, DNA Typing ) (citing Andrews v. State, 533 So.2d 841 (Fla.Ct.App. 1988), review denied, 542 So.2d 1332 (Fla. 1989)). In the years following Andrews, courts in more than forty states have considered DNA evidence in hundreds of cases. National Research Council, Summary, DNA Technology in Forensic Science 21-22 (1992) (NRC Summary, DNA Technology ). DNA contains the genetic code for all living organisms and is present in every cell containing a nucleus. Christopher G. Shank, Note, DNA Evidence in Criminal Trials: Modifying the Law's Approach to Protect the Accused from Prejudicial Genetic Evidence, 34 Ariz.L.Rev. 829, 829, 832 n. 27 (1992). DNA is composed of several component parts, including four different base pairs. See State v. Cauthron, 120 Wash.2d 879, 846 P.2d 502, 508 (1993). The precise sequence of these base pairs in certain DNA segments determines genetic traits. Id. The segments of DNA that determine these genetic traits are called alleles. State v. Pennell, 584 A.2d 513, 516 (Del.Sup.Ct. 1989). The basis for DNA identity testing is the well-accepted proposition that except for identical twins each individual has a unique overall genetic code. William C. Thompson & Simon Ford, DNA Testing: Debate Update, 28 Trial, Apr. 1992, at 52, 52 (Thompson & Ford, DNA Testing ). Present technology, however, does not permit testing of the entire DNA sequence but only of discrete, very limited DNA segments. Because 99.9% of the DNA sequence in any two people is identical, D.H. Kaye, The Admissibility of DNA Testing, 13 Cardozo L.Rev. 353, 354 (1991), accurate analysis is vital to determine whether there is a match of the remaining 0.1 percent of the DNA sequence from the samples compared. Stated very simply, [14] there are three general steps in DNA testing: 1. Creating a DNA print or profile of a sample; 2. Determining whether the prints or profiles of different samples match; and 3. If samples match, computing the probability of a random match. NRC Summary, DNA Technology at 6, 8. Cellmark used restriction fragment length polymorphism (RFLP) testing in this case. [15] Cellmark, Lifecodes Corporation, and the FBI are the three major laboratories currently performing RFLP DNA testing in the United States. Thompson & Ford, DNA Testing at 52. Testing protocols for these laboratories are not identical. NRC Summary, DNA Technology at 15; see also State v. Anderson, 853 P.2d 135, 142-43 (N.M.Ct.App.), cert. granted, 115 N.M. 145, 848 P.2d 531 (1993). [16] Defendant does not challenge DNA testing in toto. Indeed, Defendant concedes general acceptance of the underlying theory of DNA testing and its research and diagnostic uses. Rather, Defendant makes three main challenges to the admission of the DNA test results in this case: 1. The trial court erred by declining to determine before trial whether the tests were properly conducted and accurately recorded according to Cellmark's own protocol. 2. There is no general acceptance in the relevant scientific community of the procedures used by Cellmark to declare a match. 3. There is no general acceptance in the relevant scientific community of the procedures used by Cellmark to calculate the statistical probability of a random match and, thus, the court erred in admitting statistical probability opinion testimony. We first turn to the question of what standard to apply in determining admissibility. [17]