delivered the opinion of the court:
A jury сonvicted defendant, Angelo Dalcollo, of criminal sexual assault (Ill. Rev. Stat. 1989, ch. 38, par. 12 — 13(a)(1) (now 720 ILCS 5/12 — 13(a)(1) (West 1994))). The trial court sentenced defendant to nine years’ imprisonment. Defendant now appeals his conviction. We affirm.
BACKGROUND
On August 1, 1990, defendant was charged by complaint with the offense of criminal sexual assault (Ill. Rev. Stat. 1989, ch. 38, par. 12 — 13(a)(1)). Two weeks later defendant was indicted on that same offense. The indictment charged that on July 14, 1990, defendant, by use of force, committed an act of sexual penetration by inserting his penis into A.F.’s vagina.
Trial commenced on May 11, 1993, before Judge Frederick Kapala and lasted until May 17, 1993. The facts adduced at trial may be briefly stated. Additional pertinent facts will be discussed in the context of the issues raised оn appeal. A.F., the complainant, testified that on July 14, 1990, at 3 a.m., she started to walk to the Penny Pincher Cafe (the cafe) in Rockford, Illinois, to meet some friends. After walking three miles, a red El Camino with a broken right headlight drove past her, turned around, and pulled alongside her. The driver of the vehicle, whom A.F. identified in court as defendant, offered her a ride, which she accepted. As they approached the cafe, defendant "punched the gas” and drove past it. Defendant drove to a parking lot and told A.F. that he was going to "make love to [her].” When A.F tried to open her door, defendant told her "not to make him do it the hard way,” because if she did, "he’d hurt [her] really bad.” A.F. asked him if he was afraid of "going up for rape,” and he said hе was not because "he’d gone up lots of times before and never got caught.” Defendant then hit her in the head, jumped on top of her, and removed her pants. After ordering her to remove her tampon, he inserted his penis into her vagina and ejaculated. Defendant then let her leave the car. As he drove away, she memorized the license plate number. A.F. stated it was 14CC2E, although the record reveals that the number was actually 1422 CE. A.F. then walked to the cafe and told some police officers, who happened to be there, that she had been raped. The police officers took, her to the hospital. At the hospital, A.F. told the nurse that she had been raped.
A.F. also testified that on July 16, 1990, she went with her husband, Debrа Shumaker, and Gerald Anderson to defendant’s home. A.F.’s husband apparently knew that defendant was her assailant based on her description of him and his vehicle. He therefore wanted to "beat up” defendant. After their car got stuck in a ditch near defendant’s home, a truck driven by defendant pulled up behind them. When defendant said something to them, A.F. turned around, pointed at him, and said, "He is the one that raped me.” Defendant ran, but was caught and beaten by A.F.’s husband.
On cross-examination, A.F. stated that the distance from her home to the cafe was 8 to 10 miles. She stated that she touched the inside of the El Camino with her hands and that while inside the vehicle she tried to wipe off any fluids or menstrual blood on her. She admitted that she knew on July 20, 1990, that defendant had charged her with aggravated assault in relation to the July 16 incident. On redirect examination, A.F. testified that when she arrived at the cafe on July 14, 1990, she gave a description of her assailant to a police officer and told him that her assailant’s vehicle was a red El Camino with a broken right headlight.
Officer Royal MacKenzie of the Rockford police department testified that at approximately 5 a.m., on July 14, 1990, A.F. approached him in the cafe and told him that she had been raped. Her blouse was torn and she was crying. She described her assailant and his vehicle, a red El Camino pickup truck with a broken headlight. She also provided the vehicle’s license plate number. He then escorted her to SwedishAmerican Hospital.
Michelle Gillihan, a nurse at the hospital, testified that at approximately 5:45 a.m. on July 14, 1990, she met A.F., who told her that she had been raped. Gillihan then performed a rape test examination on A.F. She did not notice any bruises on A.F.
Detective Bruce Scott of the Rockford police department testified that on July 20, 1990, he impounded defendant’s vehicle, a red El Camino. The vehicle’s right headlight did not work. Detective Scott also stated that when he served the criminal complaint on defendant in this case, defendant said, "Yeah, but you can’t fucking prove it.” He acknowledged on cross-examination that when he impounded the vehicle, there was no indication that it had been recently cleaned.
Dr. Harold Deadman, supervisor of the Federal Bureau of Investigation’s (FBI) DNA analysis unit, testified as an expert in forensic DNA analysis. According to Dr. Deadman, DNA (deoxyribonucleic acid) is a chemical substance present in the cellular material of all living things. Located in a body’s chromosomes, DNA determines a person’s characteristics. DNA is made of four types of subunits, which he described as being "like links in a chain.” Although there are only four types of subunits, there are millions of individual subunits along the length of the chain. The sequence of the different subunits determines a person’s characteristics. Except for identical twins, each person’s DNA is unique.
Dr. Deadman testified that the DNA analysis unit examines evidence submitted in criminal cases by comparing the DNA extracted from an unknown source with DNA from, a рarticular person. The unit attempts to identify an individual as being a contributor of a particular type of biological material, such as blood or seminal fluid. There are three general steps in DNA testing: (1) creating a DNA "profile” of a sample; (2) determining whether the profiles of different samples "match”; and (3) if the samples match, estimating the statistical probability of a random match.
The first step, creating a DNA "profile” of a sample, involves its own six-step process, known as "Restriction Fragment Length Polymorphism” (RFLP). Step 1 involves extracting the DNA from a sample. Step 2 involves cutting the extracted DNA into smaller fragments. The DNA is cut "by using chemical substances that subjects [sic] it to certain sequences that are present,” thereby genеrating a large number of smaller fragments of DNA. In step 3, the DNA is separated by size. The DNA is placed in a gel; an electrical current is applied to the gel, forcing the DNA fragments to move according to their size. The larger fragments, which move more slowly, remain at the origin, while intermediate fragments spread throughout the gel. Once completed, the DNA fragments are arrayed across the gel according to their size. In step 4, the DNA fragments are transferred from the gel to a piece of nylon. When this is done properly, the fragments are arrayed on the nylon exactly as they existed in the gel. Step 5 involves using radioactively charged probes to identify, locate, and measure the DNA fragments of concern to the test. In step 6, the probes are "visualized.” A piece of X-ray film is placed on top of the probe, revealing DNA "bands” (pieces of DNA). DNA bands make up the DNA profile.
The second step requires interpreting the results of the RFLP procedure. Interpretation involves comparing DNA bands from known and unknown samples. A comparison may be made by visually inspecting and then measuring the DNA bands of the known and unknown samples. A "match” exists if the bands are consistent. A match between a known and unknown sample is not an absolute identification. A match is only a statement of consistency. That is, a match is a statement that the DNA in the unknown sample could have originated from the source of the known sample.
The third step involves estimating the statistical prоbability of a random match. Because a match is only a statement that the DNA in the crime scene sample could have originated from the defendant, the FBI estimates the statistical probability of a random match between the DNA sample taken from the crime scene and the DNA sample taken from the defendant. To do this, the FBI determines what part of the population would contain a DNA profile like that found in a particular case. In other words, the FBI estimates the frequency of the particular DNA test sample occurring in a population unit. In making this estimate, the FBI compares the DNA test samples to a previously constructed database. The FBI’s databases are divided along racial lines. The Caucasian database, which was used in the present case, is a database of approximately 500 to 700 people, or between 1,000 and 1,500 DNA bands.
The FBI estimates the probability of a random match in the following manner. The bands in a particular category are added up and then divided by the total numbers of bands. The result is the "band frequency” for that population unit based on the FBI database. Once the frequencies of each probe are determined, they are multiplied together to determine the frequency of the DNA profile. This manner of multiplying the frequencies is known as the product rule. A more detailed explanation of the product rule may be found in State v. Bible,
According to Dr. Deadman, the FBI’s procedures have been criticized "primarily in the courtroom, by Defense experts in the courtroom.” The FBI’s procedures have not been criticized to any great extent at scientific conferences. Moreover, the scientific literature that deals with the issues of forensic DNA evidence is "almost overwhelmingly” in support of the FBI’s procedures. Those publications that have criticized the FBI’s procedures are "very few,” and they use "very little supporting data” to support their criticisms.
Using the FBI’s procedures, Dr. Deadman concluded, to a reasonable degree of scientific certainty, that defendant’s DNA "matched” the DNA recovered from the seminal fluid found on the underwear A.F. wore at the time of the attack. Dr. Deadman calculated that the probability of a random match was 1 in 60 million.
On cross-examination, Dr. Deadman testified that the database used in the present case is used for the entire United States, but that it includes samples only from California, Texas, Florida, and FBI trainees. While there may be some differences between ethnic groups within a population, those differences are not "meaningful or significant.” Dr. Deadman conceded that it would be possible to get a different result in this case if the samples comprising the database were drawn from Illinois and that using a different database could result in a different probability of a random match. Dr. Deadman also conceded that a report by the National Research Council, Committee on DNA Teсhnology in Forensic Science, DNA Technology in Forensic Science (1992) (NRC Report), stated that "[qjuestions have been raised about the adequacy of population data bases on which frequency estimates are based on the role of ratio and ethnic origin and frequency estimation.”
The State rested at the conclusion of Dr. Deadman’s testimony. In his own defense, defendant called Dr. Pravatchai Boonlayangoor to testify as an expert in forensic DNA analysis. Using the same test data as the FBI but a different method of calculating the probability of a random match, Dr. Boonlayangoor determined that the probability of a random match could be from 1 in 745 to 1 in 4,212. Dr. Boonlayangoor admitted that his method of calculation was not recommended in the NRC Report and was even more conservative. He also admitted that his method of calculation was used by no other scientist.
Kandie Dalcollo, defendant’s wife, testified that between 2 and 3 a.m. on July 14, 1990, she heard defendant leave the house. She remained awake for the next 15 minutes, and during that time she did not hear her husband’s car start. Mrs. Dalcollo next saw defendant at 6 a.m. that day. She admitted that she did not know where defendant was between 3:30 a.m. and 6 a.m. She described defendant as having a moustache and beard on July 14, 1990. Margaret Dalcollo, defendant’s mother, testified that on July 14, 1990, at 5 a.m., she found defendant asleep in his car. She also testified that defendant’s car, an El Camino, was not operable оn July 14, 1990.
Defendant, a convicted thief, testified that on July 14, 1990, from approximately 2:30 to 5 a.m., he was asleep in his car. Between 5 and 5:10 a.m., his mother woke him. According to defendant, his car was inoperable at that time. At the conclusion of defendant’s testimony, the defense rested. After closing arguments, the jury returned a verdict of guilty.
DISCUSSION
Defendant has four principal contentions on appeal: (1) the trial court erred in admitting the DNA test results; (2) the trial court erred in denying defendant’s motion to suppress identification evidence; (3) the prosecutor’s comments in closing argument denied him a fair trial; and (4) he was not proved guilty beyond a reasonable doubt.
I
Defendant’s first contention is that the trial court erred in admitting the DNA test results. Defendant posits two alternative arguments in support of this contention: (1) the trial court erred in refusing to conduct a Frye hearing (see Frye v. United States,
A
(This material was nonpublishable pursuant to Supreme Court Rule 23.)
B
Defendant next argues that the trial court erred in admitting the DNA evidence. Defendant apparently does not challenge whether the FBI’s RFLP matching procedures are generally accepted in the relevant scientific community. Defendant instead makes one principal challenge to the admission of DNA test results in this case, namely, that the FBI’s manner of determining the statistical probability of a random match of DNA profiles is not generally accepted in the relevant sсientific community. Our subsequent analysis, therefore, will be limited to this one issue.
The admission of scientific evidence in Illinois is governed by the test set forth in Frye v. United States,
"Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.” Frye,293 F. at 1014 .
In other words, evidence is admissible when the scientific principle on which it rests has gained general acceptance in the relevant scientific community. People v. Acri,
To date, our supreme court has not addressed whether DNA test results are admissible, although it has indicated it will in the appropriate case. See Franson v. Micelli,
The Illinois Appellate Court, in contrast, has issued a multitude of opinions on this issue. See, e.g., Franson v. Micelli,
The fourth district first addressed the issue in People v. Lipscomb,
In Miles, the defendant challenged on appeal the admissibility of the DNA test results on the ground that the probability statistics, as calculated by the product rule, were inadmissible. Miles,
In People v. Watson,
Soon after Watson, the second district issued Peoрle v. Stremmel,
The fourth district reentered the debate with People v. Johnson,
In People v. Heaton,
In Franson v. Micelli,
Having reviewed the principal Illinois cases on the admissibility of DNA evidence, we now shift our attention to the case at bar. Defendant urges us to conduct a broad review of the record and consider the NRC Report, even though he never presented this report to the trial court. Defendant argues that the NRC Report establishes that the product rule method for calculating the statistical probability of a random match dоes not satisfy the Frye test because it is not generally accepted within the relevant scientific community. As such, defendant argues, the trial court erred in admitting the DNA test results.
Analytically, defendant’s argument compels us to answer three questions: (1) may we consider and rely upon legal and scientific commentaries when reviewing the trial court’s determinations regarding the admissibility of DNA evidence, even if the commentaries were not originally before the trial court? (2) are the procedures used to apply a scientific theory subject to the Frye test? and (3) if so, is the FBI’s method of calculating the statistical probability of a random match generally accepted in the relevant scientific community? As we explain below, we answеr each question in the affirmative.
(1)
The first question we must answer is whether we may consider and rely upon legal and scientific commentaries when viewing the trial court’s determinations regarding the admissibility of DNA evidence, even if the commentaries were not originally before the trial court. Defendant urges us to conduct a broad review of the record and consider materials such as the NRC Report in reviewing the trial court’s determinations.
Generally, a reviewing court will not disturb a trial court’s determination to admit evidence pursuant to the Frye standard absent an abuse of discretion. Eyler,
We note that the position we adopt today — engaging in a broad review of the trial court’s determination — accords with the practice of our supreme court when it has considered the admissibility of a scientific theory in a given case. See, e.g., Eyler,
(2)
Having answered the first question in the affirmative, we must now answer the second: are the procedures used to apply a scientific theory subject to the Frye test? Under the Lipscomb/Miles line of cases, the procedure for calculating probability statistics is not subject to the Frye test. Rather, probability statistics are admissible because the DNA evidence in general satisfied the Frye test. As Miles explained:
"Implicitly, the [Lipscomb] court held the process of generating probability statistics is an integral part of the DNA identification process. Because the DNA identification process meets the Frye test and is admissible, probability statistics operated thereby are admissible.” Miles,217 Ill. App. 3d at 405 .
We disagree. In our view, application of the Frye test to determine the admissibility of DNA evidence requires that both the theory and the techniques or procedures implementing the theory must be generally accepted in the relevant scientific community. See Franson,
First, Frye requires that the "thing” from which the deduction is made — e.g., the procedures upon which the DNA results are based— must be generally accepted. Undoubtedly, the theory behind DNA testing is generally accepted. Contrary to the position espoused by the Lipscomb/Miles line of cases, however, the procedures used to implement the theory are still subject to the Frye test. As the Fran-son court cogently explained:
"Under Frye, if the procedure or 'thing’ upon which the DNA result was determined is not generally accepted, then the result is inadmissible. For instance, DNA testing to determine a 'match’ may be well recognized, but the 'thing’ upon which the result is based is the procedure used to arrive at the determination of whether there is a 'match.’ Thus, if the procedures are not generally accepted, then the result is inadmissible under Frye. Similarly, although it may be generally accepted that statistical probabilities can be calculated based upon the 'matching’ results, if the method used to calculate the statistical probabilities is not generally accepted as valid in the relevant scientific community, then the statistics should be inadmissible.” Franson,269 Ill. App. 3d at 29-30 .
Sеcond, merely " '[bjecause the DNA identification process meets the Frye test’ ” does not mean that " 'probability statistics operated thereby’ ” are admissible. Franson,
Accordingly, we hold that the Frye test requires that both the theory and the techniques or procedures implementing the theory must be generally accepted in the relevant scientific community. See Franson,
(3)
We now arrive at the heart of the contention — whether the FBI’s method of calculating the statistical probability of a random match is generally accepted in the relevant scientific community. Defendant maintains that the NEC Report and other scientific commentaries demonstrate that probability statistics are not generally accepted. He therefore asks us to reverse his conviction and remand the cause for a new trial.
In determining whether a novel scientific procedure is "generally accepted” in the scientific community, the issue is consensus versus controversy over a particular technique. Porter,
With these principles in mind, we now turn to whether the FBI’s method of calculating the statistical probability of a random match is generally accepted in the relevant scientific community. As Dr. Deadman testified, a match is only a statement that the DNA in the crime scene sample could have originated from the defendant. The FBI therefore estimates, by using the product rule, the statistical probability of a random match between the DNA sample taken from the crime scene and the DNA sample taken from the defendant. In other words, the FBI estimates the frequency of the particular DNA test sample occurring in a population unit. In making this estimate, the FBI compares the DNA samples to a previously constructed population database.
According to the scientific literature, the product rule relies on two assumptions, both of which must exist for its calculations to be аccurate. The first, known as "Hardy-Weinberg equilibrium,” assumes that the members of the racial groups represented in the databases mate randomly within their group and thus mix the gene pool evenly. The second, known as "linkage equilibrium,” assumes that the DNA bands identified by the RFLP procedures are not related to each other and thus are independent in a statistical sense. See generally R. Lewotin & D. Hartl, Population Genetics in Forensic DNA Typing, 254 Science 1745 (1991) (Lewotin & Hartl); see also State v. Johnson,
Although DNA test results have been admitted in criminal cases since 1988 (see People v. Wardell,
We will not add to the already voluminous materials that have described the nature of the debate that developed as a result of the foregoing publications. Suffice it to say that the debate centered on the possibility of subgrouping among populations. Subgrouping is based on the premise that census pоpulations designated "Caucasian,” "Black,” or "Hispanic” actually consist of multiple genetically diverse subpopulations. If subgrouping occurs, then some scientists and population geneticists opine that it may cause both Hardy-Weinberg and linkage disequilibrium, which would render statistical probability calculations inaccurate. See Lewotin & Hartl, at 1746. For the curious reader, a more detailed account of the debate is located in the following materials: Watson,
Riding the crest of this alleged "bitter debate” (see L. Roberts, Fight Erupts Over DNA Fingerprinting, 254 Science 1721, 1723 (1991)), some courts have rejected testimony on probability statistics on the ground that the calculations were not generally accepted in the scientific cоmmunity. See, e.g., Bible,
We need not decide whether these cases were properly decided. Even if the foregoing publications ignited a "bitter debate” in the scientific community, and thus demonstrated that the calculation of probability statistics was not generally accepted in the scientific community, the debate has clearly calmed in the last several years. This calming is attributable to two developments not considered by the fоregoing cases.
The first is the recognition by scientists that more conservative methods to calculate statistical probabilities do not create a corresponding reduction in random match probability calculations. The NRC Report recommended that scientists use the ceiling principle, as opposed to the product rule, to calculate statistical probabilities. However, Eric Lander, an early critic of the use of probability statistics, as well as a coauthor of the NRG Report, and Bruce Budowle, one of the principal architects of the FBI’s DNA program, have observed that the use of this more conservative method does not create a corresponding reduction in randоm match probability calculations. See E. Lander & B. Budowle, DNA Fingerprinting Dispute Laid to Rest, 371 Nature 735 (1994).
The second development is the FBI’s completion of an exhaustive worldwide population survey, a survey which was recommended by the NRG Report. See United States Department of Justice, Federal Bureau of Investigation, I-A VNTR Population Data: A Worldwide Study (1993) (FBI Study), cited in People v. Amundson,
These developments clearly debunk the notion that a "bitter debate” — if ever there was one — is still raging in the scientific community. Thus, we conclude that thе FBI’s calculation of statistical probabilities, as derived by the product rule, is generally accepted in the scientific community. Accord Amundson,
We note that our holding today is distinguishable from those reached in prior Illinois cases. In the Lipscomb ! Miles line of cases, the courts did not consider the compelling materials we do today. Similarly, although the Watson and Franson courts considered some of these materials, they did not consider all of them.
II
CONCLUSION
For the foregoing reasons, the judgment of the circuit court of Winnebago County is affirmed.
Affirmed.
COLWELL and RATHJE, JJ., concur.
Notes
Recently, the supreme court vacated Franson and dismissed the appeal on the ground that both it and the appellate court lacked jurisdiction to hear the appeal. However, we find much of the Franson court’s reasoning instructive and therefore refer to it in our decision.