Court Opinion

ID: 9608342
Source: CourtListenerOpinion
Date Created: 2023-08-22 03:10:54.766984+00
Date Added: 2024-06-11T11:27:43.973118
License: Public Domain

MARTONE, Justice,
concurring.
This is our third attempt to deal with the complexity of DNA. I write to suggest an approach that acknowledges our limitations. In State v. Bible, 175 Ariz. 549, 858 P.2d 1152 (1993), and State v. Johnson, 186 Ariz. 329, 922 P.2d 294 (1996), we worked hard to come to an understanding of a vast body of knowledge. Despite our genuine efforts, we now know that we misunderstood many intricate scientific principles. This is understanda*128ble — we are not trained scientists. Happily, our mistakes did not affect the results. But our reasoning was flawed by an imperfect understanding of the science of DNA. Two of many mistakes follow.
One reason we rejected statistical probabilities calculated using the product rule in Bible was that “the database relied on [was] not in Hardy-Weinberg equilibrium.” Bible, 175 Ariz. at 586, 858 P.2d at 1189. But in Bible, this perceived flaw would have benefited the defendant, and thus, was not a reason to exclude product rule estimates. David H. Kaye, Bible Reading: DNA Evidence in Arizona, 28 Ariz. St. L.J. 1035, 1055 (forthcoming 1997). Additionally, the expert testimony showed that the database was consistent with a population in Hardy-Weinberg equilibrium. Id. at 1056-57.
So too, in Johnson, we allowed expert testimony on the significance of a match using the modified ceiling method, in part because “the NRC report makes clear, the assumption of linkage equilibrium ... is well-grounded.” Johnson, 186 Ariz. at 332, 922 P.2d at 297. But the modified ceiling method was developed to be used in case linkage equilibrium did not exist. Kaye, supra at 1064^65. Because the modified ceiling method is generally accepted in the scientific community, we nevertheless reached the right result.
Notwithstanding these and other problems, the majority relies on Bible and Johnson as though we had not erred, and tries again to explain the science of DNA. I would not continue down this path. I believe it is time for us to acknowledge that it is neither necessary nor possible .for us to understand the science of DNA. It is enough that legitimate scientists do, and that DNA principles are generally accepted in the relevant scientific community.
We use the Frye standard under which the proponent of scientific evidence must establish that the underlying scientific principle is generally accepted in the relevant scientific community. Frye v. United States, 293 F. 1013, 1014 (D.C.Cir.1923). “Frye requires nothing more.” Fishback v. People, 851 P.2d 884, 891 (Colo.1993). Frye does not suggest that judges must become experts in the science behind the evidence. Rather, judges are to survey the relevant scientific literature, not for substantive content, but to determine the level of acceptance within the scientific community.5 We would not have erred in Bible had we stopped at the point of acknowledging that the product rule was not then generally accepted. We would not have erred in Johnson had we merely acknowledged that the modified ceiling method was.
Of course, a general understanding of the underlying science can only help the decision making process. But there are limits. It is not our task to resolve scientific issues. Nor should we presume to speak the vocabulary of science.6 I would leave the task of describing the details of new scientific principles to scientists.
In contrast, the question of admissibility is ours to make. We cannot delegate its resolution to scientists. There are two legal issues. The first is whether the DNA methodology used to determine a match satisfies Frye. The second is whether an expert may testify about the significance of a match, either quantitatively or qualitatively.
1. DNA methodology
The controversy that initially surrounded DNA typing has been resolved. Courts no longer question “[t]he biological and technological principles underlying the forensic methods for characterizing DNA variations.” National Research Council (NRC), The Eval*129nation of Forensic DNA Evidence 6-5 (1996) (prepublication copy).
In Bible and Johnson, we recognized the reliability of forensic DNA typing using the RFLP method. This case also involves the RFLP approach. “[T]he theory underlying DNA and RFLP technology is not generally open to serious attack----” State v. Moore, 268 Mont. 20, 885 P.2d 457, 468 (1994). Thus, the only unresolved issue in this case is whether expert testimony on the significance of a DNA match is admissible.
2. Expert interpretation of a DNA match
This court has twice addressed the second issue — the significance of a match. On both occasions, the controversy involved quantitative interpretations of the match.
In Bible, we decided that the product rule was not generally accepted at the time. Three years later, in Johnson, we held that the modified ceiling method was generally accepted in the relevant scientific community and, therefore, testimony on the statistical significance of a DNA match calculated under that method was admissible.
The product rule and the ceiling method are based on mathematical formulae. These in turn are based on statistics and population genetics. Brim v. State, at *2, 695 So.2d 268, 270 (Fla. Jan. 16,1997). Because the scientific community is in the best position to determine whether a formula is reliable, Frye governs. See id. at *3, at 270.
This case is unlike Bible and Johnson because it involves a qualitative, not quantitative, description of the significance of a match. The experts in this ease testified that they had never seen two samples from unrelated donors that matched over three probes, that the possibility of a random match was “rare,” and that DNA can “uniquely identify” a person. These conclusions were based upon their own scientific experience. Neither expert relied upon a controversial scientific principle. I agree with the court, therefore, that Frye is not applicable. The experts’ opinions concerning the “uniqueness of DNA” and their personal experience are admissible under Rule 702, Ariz. R. Evid. The data supporting them opinions are admissible under Rule 703, Ariz. R. Evid.
We are judges, not scientists. It is enough for us to be able to identify the legitimacy of a principle and its proponents so as to exclude junk science. Qualitative descriptions of the significance of a match are admissible.

. Frye does not ask judges to engage in a numbers game. General acceptance is determined by considering “the quality, as well as quantity, of the evidence supporting or opposing a new scientific technique. Mere numerical majority support or opposition by persons minimally qualified to state an authoritative opinion is of little value....” People v. Leahy, 8 Cal.4th 587, 34 Cal.Rptr.2d 663, 882 P.2d 321, 336-37 (1994).

. I recognize that some cases may require the court to give a very basic overview of the underlying science. The present case, however, does not hinge upon scientific principles. This case involves the Rules of Evidence, not the application of a scientific principle. See infra at 128-129, 933 P.2d at 1196-97. The court's explanation of forensic DNA typing is, therefore, unnecessary. See ante at 122-123, 933 P.2d at 1190-91.