Young v. State

RAKER, Judge. The primary issue we address in this appeal is whether the trial court erred in admitting evidence that there was a DNA “match” in the absence of accompanying statistical evidence. We conclude that the court did not err and hold that when a DNA method analyzes genetic markers at sufficient locations to arrive at an infinitesimal random match probability, expert opinion testimony of a match and of the source of the DNA evidence is admissible. ¹⁰¹ I. The Grand Jury for Prince George’s County charged Anthony Eugene Young with, inter alia, three counts of second degree sexual offense and three counts of third degree sexual offense. A jury in Prince George’s County convicted petitioner of one count of second degree sex offense.

At trial, the State presented the following evidence: On September 27, 2001, a thirteen year-old boy participated in an internet chat room called “Gay Twenties.” Young, who was thirty-seven at the time, participated in the chat room as well. Young contacted the boy via instant messenger 1 and telephone and arranged a rendezvous at the boy’s apartment. The next day, Young visited the boy’s home, and the two engaged in oral and anal sex. On October 2, Young visited the boy’s home unannounced and again engaged him in anal sex.

During the second encounter, the boy’s mother returned home from work. After Young left, the boy eventually disclosed to his mother what had occurred. Later that night, the mother and child contacted the police. The boy was taken to the hospital where he was examined.

Identification was the primary issue at trial. The State offered three types of identification evidence. First, the State presented testimonial evidence, primarily that of the boy. Young challenged the testimonial evidence, emphasizing the boy and his mother’s failure to identify Young in a police photo array and claiming that the boy was not credible.

Second, the State tendered evidence that Young participated in the chat room. Young did not dispute that evidence. 2 Third, the State presented DNA evidence. ¹⁰² The DNA evidence consisted of an analysis of two DNA samples. The first was obtained from the boy by a forensic nurse who examined him at the hospital and took a swab of his rectal area. The second was procured by an officer of the Prince George’s County Police Department who, with Young’s consent, took two swabs of Young’s mouth.

In this appeal, Young challenges the testimony of Rupert Page, a forensic DNA analyst for the Prince George’s County Police Department, who examined the samples on behalf of the State. The court received Page as an expert in profiling and forensic serology. Page testified that other than identical twins, no two people have the same DNA profile. He then described his testing of the anal swabs from the boy and the oral swabs from Young.

Page explained that he used a process called differential extraction to separate the sperm cells from the boy’s skin cells on the anal swab. He testified that he made a microscope slide of the sperm cells, obtained a DNA profile from the slide, and compared the profile to Young’s profile obtained from the oral swabs. In response to the State’s questions, Page repeatedly testified that the two DNA profiles “matched.” Page did not provide any basis for this conclusion, other than to state that his conclusion was based on his comparison of the two samples. He did not identify which DNA sequences he reviewed, and only on cross-examination did he note that he employed the polymerase chain reaction (“PCR”) method.

Page did not testify to the probability that a random person’s profile would have matched the profile taken from the boy. Defense counsel objected repeatedly, arguing that, based on Armstead v. State, 342 Md. 38 , 673 A.2d 221 (1996), the witness was required to provide probability statistics to accompany and support his conclusion. For example, defense counsel stated as follows: “Your Honor, the Armstead case concluded.... My understanding is that the Court of Appeals concluded that the legislature intended to render the sexual statistics admissible, not just the raw evidence of DNA match, and what the State seems to be trying to do is to say there is a match as ¹⁰³ opposed to providing what the statistical information was that was provided to give the jury a chance to make that determination.” The court permitted the witness to testify that the DNA profiles “matched,” but did not allow him to testify that Young was the source of the DNA obtained from the anal swab.

Instead, the court admitted into evidence Page’s DNA report, over defense counsel’s objection. In this report, Page noted that he employed the PCR method and the AmpFISTR Profiler Plus PCR Amplification Kit and AmpFISTR Cofiler PCR Amplification Eat to examine DNA markers along a combined thirteen loci and a gender identification locus. 3 Page concluded, “The sperm fraction of the Anal Swab (Rl) contains DNA from a male. To a reasonable degree of scientific certainty (in the absence of an identical twin), Anthony Young (Kl) is the source of the DNA obtained from the sperm fraction of the Anal Swab (Rl).” 4 Page’s report contained no statistical data to support his conclusion. Young’s cross-examination of Page focused on the whereabouts of a particular piece of evidence not presented at trial and on the significance of Page’s references to “technical artifacts” in his comparison of the DNA samples.

Young did not ask Page any questions about statistics. The State relied heavily on the evidence that the DNA samples matched. In its opening statement, the State argued that the DNA evidence showed “a perfect match, all the way down the line” and that the “DNA evidence will prove conclusively that Anthony Young was the source of the semen recovered from [the victim’s] anus, removing any doubt you may have whatsoever, leading to the only conclusion, and that is the conclusion that Anthony Young is guilty of the charges submitted to you.” In its closing statement, the State argued ¹⁰⁴ that the DNA evidence revealed “an exact match” “straight down the line.” In its rebuttal argument, the State responded to Young’s challenges to the testimony of identification and the victim’s credibility by pointing to the DNA evidence. In response to Young’s emphasis of the failure to identify him in the photo array, the State said, “That’s a red herring.

You know why? Because it doesn’t make any difference, because the DNA says it was Anthony Young who had anal intercourse with [the victim]. So don’t be fooled by that.” The jury found Young guilty of one count of second degree sexual offense. The court sentenced Young to a term of twenty years incarceration.

Young noted a timely appeal to the Court of Special Appeals. In an unreported opinion, that court affirmed. The Court of Special Appeals appears to have relied on two bases. First, the court distinguished Armstead v. State, 342 Md. 38 , 673 A.2d 221 (1996).

The court explained that while a DNA match based on a comparison of one locus is virtually meaningless without accompanying statistical testimony, a match at thirteen different loci has such a low random match probability that there is no requirement of accompanying statistical data. Second, the court held that even if statistical evidence were required, the error was harmless beyond a reasonable doubt. We granted Young’s petition for a Writ of Certiorari. 384 Md. 157 , 862 A.2d 993 (2004). Young raises the following issue: “Whether it was error to admit ‘expert testimony’ that there was a DNA ‘match’ in the absence of any foundation for such an assertion.” We agree with the Court of Special Appeals and hold that the Circuit Court did not err in admitting the expert’s testimony of a match in conjunction with testimony that to a reasonable degree of scientific certainty, the defendant was the source of the DNA evidence.

Accordingly, we affirm. ¹⁰⁵ II. In this Court, Young argues that the trial court erred in overruling his objections to Page’s testimony. He contends that Armstead requires the admission of contextual statistics when the State asserts that there is a DNA match. According to Young, stating that DNA profiles match without providing the statistical probability is meaningless, because DNA statistics vary based on the defendant’s ethnic group or the number of loci examined.

In Young’s view, Page’s testimony thus had no probative value and was irrelevant. The State responds that the DNA evidence was relevant and admissible, without any testimony about statistical probability. According to the State, Armstead did not require testimony about statistical probability. Rather, this Court’s strong statements about the admissibility of statistical probability testimony should be viewed in the context of Armstead’s questioning of the testimony’s admissibility and the controversy within the scientific community about the validity of such evidence.

In addition, the State argues that scientific advances in DNA testing since Armstead have eliminated any uncertainty about the meaning of the term “match.” The State contends that in all cases, the probability that another person besides an identical twin has the same DNA profile has become so remote that an expert witness can testify to a DNA match without explaining the statistical probability. In the alternative, the State argues that even if the court erred, the error was harmless beyond a reasonable doubt. Given the scientific advancements resulting in a remote probability that another individual has an identical profile to Young, the jury could not have been swayed by testimony of the probability. We conclude that scientific advances in DNA profiling enable an examiner employing particular methods and analyzing genetic markers at a sufficient number of loci to testify, to a reasonable degree of scientific certainty, to the source of the DNA evidence.

We hold that in such circumstances, as in the instant case, the expert is not required to accompany his “match” testimony with contextual statistics. Accordingly, the ¹⁰⁶ Circuit Court did not err in admitting the expert’s testimony of a match.

III

We have described the science of DNA evidence as follows: “Deoxyribonucleic acid (‘DNA’) is the organic material that provides the genetic instructions for all individual hereditary characteristics. See Armstead v. State, 342 Md. 38, 51 , 673 A.2d 221, 227 (1996); United States v. Hicks, 103 F.3d 837, 844 (9th Cir.1996); Commonwealth v. Curnin, 409 Mass. 218 , 565 N.E.2d 440 , 441 n. 1 (1991); State v. Carter, 246 Neb. 953 , 524 N.W.2d 763, 775 (1994), overruled on other grounds, State v. Freeman, 253 Neb. 385 , 571 N.W.2d 276 (1997); State v. Vandebogart, 136 N.H. 365 , 616 A.2d 483, 485 (1992); State v. Cauthron, 120 Wash.2d 879 , 846 P.2d 502, 508 (1993). The importance of DNA for forensic purposes is that DNA does not vary within an individual and, with the exception of identical twins, no two individuals have the same DNA configuration. See Nelson v. State, 628 A.2d 69, 75 (Del.1993); State v. Williams, 574 N.W.2d 293, 297 (Iowa 1998); Curnin, 565 N.E.2d at 441 n. 1, 445; Carter, 524 N.W.2d at 775 ; Vandebogart, 616 A.2d at 485-86 ; State v. Copeland, 130 Wash.2d 244 , 922 P.2d 1304, 1315 (1996); George Bundy Smith & Janet A. Gordon, The Admission of DNA Evidence in State and Federal Courts, 65 Fordham L.Rev. 2465, 2465 (1997). “The molecular structure of DNA is commonly referred to as a ‘double helix,’ which resembles a spiraling ladder, and which is composed of twisted double strands of repeated sequences of ‘nucleotides.’ See Armstead, 342 Md. at 51 , 673 A.2d at 227 ; State v. Tankersley, 191 Ariz. 359 , 956 P.2d 486, 490 (1998); Williams, 574 N.W.2d at 297 ; Curnin, 565 N.E.2d at 445 ; Carter, 524 N.W.2d at 775 ; Vandebogart, 616 A.2d at 486 ; Copeland, 922 P.2d at 1315 ; Smith & Gordon, supra, at 2465-66.

The sides of the ladder are composed of the ‘nucleotides,’ which are organic bases that pair with one another to form the ‘rungs’ of the double helix. See Curnin, 565 N.E.2d at 445-46 ; Carter , 524 N.W.2d at ¹⁰⁷ 775; Cauthron, 846 P.2d at 508 ; Smith & Gordon, supra, at 2466. It is the repeating sequence of base pairs along the DNA double helix that comprise ‘genes,’ which determine the unique physiological traits of human beings. See Armstead, 342 Md. at 51-52 , 673 A.2d at 227 ; Hicks, 103 F.3d at 845 ; Tankersley, 956 P.2d at 490 n. 2; Carter, 524 N.W.2d at 775 ; Vandebogart, 616 A.2d at 486 ; Cauthron, 846 P.2d at 508 ; Smith & Gordon, supra, at 2466.

The specific position that a gene occupies is called its ‘locus.’ See Smith & Gordon, supra, at 2466. An individual’s entire complement of DNA is known as the ‘genome.’ See Vandebogart, 616 A.2d at 486 ; Smith & Gordon, supra, at 2467. “The vast majority of the base pair sequences of human DNA are identical for all people. See Armstead, 342 Md. at 52 , 673 A.2d at 227 ; Hicks, 103 F.3d at 845 ; Nelson, 628 A.2d at 75 ; Williams, 574 N.W.2d at 297 ; Carter, 524 N.W.2d at 775 ; Copeland, 922 P.2d at 1315 ; Smith & Gordon, supra, at 2466. There are, however, a few DNA segments or genes, called ‘polymorphic loci,’ which are highly variable among individuals.

See Nelson, 628 A.2d at 75 ; Williams, 574 N.W.2d at 297 ; Curnin, 565 N.E.2d at 446 ; Carter, 524 N.W.2d at 775 ; Vandebogart, 616 A.2d at 486 ; Cauthron, 846 P.2d at 509 . The alternative forms of these individual polymorphic gene fragments are called ‘alleles.’ See Tankersley, 956 P.2d at 490 n. 2; Curnin, 565 N.E.2d at 446 ; Cauthron, 846 P.2d at 509 ; Smith & Gordon, supra,, at 2466. It is these polymorphisms that have great significance for forensic DNA analysis because they provide the basis for DNA identification. See Armstead, 342 Md. at 52 , 673 A.2d at 227 ; Hicks, 103 F.3d at 845 ; Nelson, 628 A.2d at 75 ; Curnin, 565 N.E.2d at 441 n. 1, 446; Cauthron, 846 P.2d at 509 ; Smith & Gordon, supra, at 2467.” Gross v. State, 371 Md. 334 , 339 n. 1, 809 A.2d 627 , 630 n. 1 (2002). 5 ¹⁰⁸ The polymerase chain reaction (“PCR”) method of DNA analysis is an amplification procedure that reproduces repeatedly a short segment of DNA, making it possible to analyze minute or degraded samples. 6 See United States v. Hicks, 103 F.3d 837, 845 (9th Cir.1996); State v. Tankersley, 191 Ariz. 359 , 956 P.2d 486, 489-90 (1998); Committee on DNA Forensic Science, National Research Council, The Evaluation of Forensic DNA Evidence 70 (1996) [hereinafter “NRC II”].

PCR analysis begins with a three-step process to amplify the DNA sample: (1) denaturization (the DNA is heated to separate the two strands); (2) annealing (primers containing nucleotide sequences that are complementary to the DNA ¹⁰⁹ region being amplified are added to the DNA sample, which bond to the gene when cooled); (3) extension (the gene is “copied” repeatedly in order to produce a larger sample of DNA for analysis). See Hicks, 103 F.3d at 845 . The PCR method can be carried out in a laboratory, with results obtained in a significantly shorter time than with the previously common restriction fragment length polymorphism (“RFLP”) analysis. NRC II at 70.

Additionally, the PCR method usually permits an exact identification of each allele, sidestepping RFLP’s measurement uncertainties. Id. These advantages, along with the method’s utility for analyzing minute DNA samples, have resulted in a vast expansion in the use of the PCR method. Id.; see State v. Belken, 633 N.W.2d 786, 798 (Iowa 2001) (noting that “the PCR method has emerged as the predominant method of DNA typing”).

Once PCR amplification has been completed, analysis of the DNA profile and match determination can be conducted through the utilization of several different genetic markers. See Tankersley, 956 P.2d at 490 . The markers employed by the laboratory in the instant case are short tandem repeats (“STR”). STRs are DNA sequences consisting of two to six base pairs.

See Commonwealth v. Rosier, 425 Mass. 807 , 685 N.E.2d 739, 742 (1997); John M. Butler & Christopher H. Becker, U.S. Dep’t of Justice, Improved Analysis of DNA ShoH Tandem Repeats With Time-of-Flight Mass Spectrometry 2 (2001). STRs particularly are useful in analyzing small DNA samples, because loci containing STRs are present with great frequency throughout the chromosomes. See Rosier, 685 N.E.2d at 742 . The loci have a large number of alleles and usually are susceptible to unique identification.

Id. The FBI has designated thirteen core STR loci and a sex-typing marker (amelogenin) for identification in its national database of convicted felons, the Combined DNA Index System (“CO-DIS”). See Butler & Becker, supra, at 2. 7 ¹¹⁰ DNA profiling typically is used to compare a suspect’s DNA with a sample of DNA taken from a crime scene. See Amstead, 342 Md. at 52, 673 A.2d at 228 . “DNA profiling” is a catch-all term for a wide range of methods employed to study genetic variations, including RFLP and PCR/STR typing.

See Tankersley, 956 P.2d at 491 . All types of DNA analysis involve three basic steps: (1) processing or typing of the DNA samples (to produce x-ray films that indicate the lengths of the polymorphic fragments); (2) match determination (comparison of the films to determine whether any sets of fragments match); and (3) statistical analysis (to determine the statistical significance of any match between the two DNA samples). See id.; Nelson v. State, 628 A.2d 69, 75 (Del.1993). This three-step process produces two distinct, but interrelated, types of information: (1) molecular biological information (whether a match exists between an unknown DNA sample and a sample taken from a suspect); and (2) population genetics information (if a match exists, the statistical probability that the unknown sample came from a third party with the same DNA pattern as the suspect).

See Nelson, 628 A.2d at 75 . DNA evidence cannot be attributed conclusively to one person unless examiners analyze the entire DNA molecules of the DNA evidence and the DNA sample from that person respectively. Two unrelated individuals can have identical DNA fragments that are examined in a particular type of DNA analysis — i.e., identical DNA patterns at the targeted loci. See Nelson, 628 A.2d at 75 ; State v. Williams, 574 N.W.2d 293, 297 (Iowa 1998); State v. Vandebogart, 136 N.H. 365 , 616 A.2d 483, 486 (1992); State v. Cauthron, 120 Wash.2d 879 , 846 P.2d 502, 513 (1993) (en banc).

The underlying theory of the forensic use of DNA testing is that as the number and variability of the polymorphisms analyzed increases, the odds of two people coincidentally sharing the ¹¹¹ same DNA profile becomes vanishingly small. Williams, 574 N.W.2d at 297 ; see also Commonwealth v. Crews, 586 Pa. 508 , 640 A.2d 395, 401 (1994). Therefore, when a DNA “match” has been declared, a conclusive identification of a crime suspect as the source of the unknown DNA sample is not being made. Rather, the suspect simply has been “included” as a possible source of the DNA material, because the suspect’s DNA sample has matched the crime scene DNA sample at a certain number of critical alleles.

See Tankersley, 956 P.2d at 490 ; Williams, 574 N.W.2d at 297 ; Vandebogart, 616 A.2d at 486 ; Crews, 640 A.2d at 401 ; George Bundy Smith & Janet A. Gordon, The Admission of DNA Evidence in State and Federal Courts, 65 Fordham L.Rev. 2465, 2472 (1997). The issue still remains of just how many other people in the population could share the same DNA profile with the suspect. See Tankersley, 956 P.2d at 490 ; Smith & Gordon, supra, at 2486. Once a DNA match determination has been made, forensic scientists perform statistical analysis of population frequencies to estimate the statistical significance of the match, by calculating the likelihood that a random person (i.e., not the person whose DNA actually was left at the crime scene) would match the crime scene sample, commonly referred to as the “random match probability.” See Tankersley, 956 P.2d at 490 ; Nelson, 628 A.2d at 75 ; Williams, 574 N.W.2d at 297 ; Watts v. State, 733 So.2d 214, 224 (Miss.1999) (en banc); Vandebogart, 616 A.2d at 486, 488 ; Smith & Gordon, supra, at 2473.

In order to make a statistical evaluation of a declared match, it is necessary to know how frequently a genotype occurs in the relevant reference population. See State v. Carter, 246 Neb. 953 , 524 N.W.2d 763, 776, 780 (1994). Genotype frequency calculations are performed to determine the relative frequency of a random match within a sample population database. See Commonwealth v. Curnin, 409 Mass. 218 , 565 N.E.2d 440, 448 (1991); Carter, 524 N.W.2d at 780 ; Vandebogart, 616 A.2d at 488 ; Smith & Gordon, supra, at 2473. ¹¹² The statistical significance of a match is determined by a two-step process: first, an initial determination is made regarding the random match probability of each polymorphic locus (the “individual allele frequency”); second, the individual allele frequencies are combined to determine the overall probability of possessing the entire matched DNA segment (the “aggregate DNA profile frequency”).

See Curnin, 565 N.E.2d at 448 ; Watts, 733 So.2d at 225 ; Vandebogart, 616 A.2d at 488 ; Smith & Gordon, supra, at 2473. These probability estimates are achieved using theoretical population genetics models in order to determine the frequency with which a given genetic pattern will occur in a defined population. See Watts, 733 So.2d at 225 ; Vandebogart, 616 A.2d at 488 ; Smith & Gordon, supra, at 2473-74. Probability calculations generally are made using the “product rule.” The product rule, also known as the “multiplication method,” states that the likelihood of a match occurring for an entire DNA segment can be determined by calculating the match probability for each polymorphic allele and then multiplying those probabilities together.

See Armstead, 342 Md. at 69-70 , 673 A.2d at 236 ; Williams, 574 N.W.2d at 297 ; Curnin, 565 N.E.2d at 448 ; Watts, 733 So.2d at 224-25 ; Vandebogart, 616 A.2d at 488 ; Cauthron, 846 P.2d at 513 . To give a basic example, if a matching DNA sample contains two independent alleles, and there is a 10% chance of a random match of the first allele and a 20% chance of a random match of the second, the product rule would suggest that there was a two percent chance that a random person in the population shared the same DNA profile (.10 x .20 = .02).

IV

The State argues that recent scientific advances in DNA analysis have resulted in infinitesimal random match probabilities, thus eliminating the necessity for the State to accompany match evidence with statistical evidence. The State is correct, to a large degree. The State is incorrect, however, in claiming that all techniques for analyzing DNA evidence produce infinitesimal random match probabilities. ¹¹³ Nine years have passed since Armstead was decided. 8 As DNA analysis technology advances, examiners can utilize more precise techniques and view more loci. The fact remains that a match cannot identify the source of the relevant DNA sample conclusively unless the entire DNA molecule is viewed.

Under certain circumstances, however, new technologies result in infinitesimal random match probabilities that would be deemed conclusive by all but mathematicians and philosophers. The instant case thus confronts us -with the question of whether and to what extent these scientific advances have ¹¹⁴ altered the holding of Armstead that contextual statistics must accompany match testimony. Central to this question is whether, in such cases, a trial court may permit testimony of “source attribution.” A witness testifying to “source attribution” or “uniqueness” 9 would state that in the absence of identical twins, it can be concluded to a reasonable scientific certainty that the evidence sample and the defendant sample came from the same person (i.e. from the same source). See L.M. Goos et al., The Influence of Probabilistic Statements on the Evaluation of the Significance of a DNA Match, 35 Can.

Soc’y Forensic Sci. 77, 81 (2002). Source attribution would fulfill the need to give meaning to the term “match.” Source attribution would inform the jury that the matching patterns are as unique as the Mona Lisa, and not as common as a picture with two eyes or even a four-leaf clover. 10 The first report of the National Research Council unambiguously presented accompanying statistical testimony as necessary and emphasized the inappropriateness of testifying to the ¹¹⁵ uniqueness of the genotype. The National Research Council recognized the potential for unique identification, but noted that the typing systems employed at that time did not examine enough loci. The report stated as follows: “Can DNA typing uniquely identify the source of a sample?

Because any two human genomes differ at about 3 million sites, no two persons (barring identical twins) have the same DNA sequence. Unique identification with DNA typing is therefore possible provided that enough sites of variation are examined. “However, the DNA typing systems used today examine only a few sites of variation and have only limited resolution for measuring the variability at each site.” Committee on DNA Forensic Science, National Research Council, DNA Technology in Forensic Science 74 (1992) [hereinafter “NRC I”]. The report then concluded that “[t]o