• DNA, an acronym for deoxyribonucleic acid, is the genetic material found in the nucleus of our cells; it provides the master plan for the cells of our body. Ninety-nine percent of everyone's DNA is exactly the same. The remaining small percentage is unique to each individual but identical twins.
• DNA is structured in a double helix which, if straightened out, resembles a ladder. Each rung of the ladder is made of a pair of bases, of which there are four possibilities: adenine (A), guanine (G), cytosine (C), and thymine (T). To form the rungs, A always pairs with T and G always pairs with C. Thus, if the sequence on one side of a DNA strand is known, then the other side can be determined.
• A gene is a segment of DNA and can comprise varying numbers of base pairs. Some genes are located on regions of the DNA which are called polymorphic sites; these sites contain the variability which make each of us unique. Each of the individual possibilities at a polymorphic site is called an allele. We receive one allele from each parent. If we receive the same allele from each parent, then we are homozygous at that site. If we receive a different allele from each parent, then we are heterozygous at that site. The combination of alleles for a gene is commonly referred to as its genotype.
• For example, if there are only two possible alleles at a particular site (A or B), then a person can have two homozygous genotypes (AA or BB) or one heterozygous genotype (AB). As another example, if there are three possible alleles at a particular site (A, B, or C), then a person can have three homozygous genotypes (AA, BB, or CC) and three heterozygous genotypes (AB, AC, or BC).
• Based upon the foregoing knowledge, scientists are able to analyze a DNA sample.
Methods of analyzing a DNA sample
• One method . . . is the Polymerase Chain Reaction (PCR). PCR is a method by which chosen short polymorphic segments of a DNA strand can be amplified (or copied) millions of times. This amplification is done in steps. Essentially what happens is that a double strand of DNA is separated by heat into its single strands. Then, specified areas of each DNA strand are marked and replicas are made so that there are now two identical double strands of that area. This process is repeated 20-35 times, thus producing an enormous number of copies of the original marked strand. The PCR process makes it possible to analyze what was originally a very small quantity of DNA. Once a large enough sample of DNA exists, tests can be done on the sample to determine what alleles are present at the specified areas. . . . Based on the genotypes of [the specified areas], the scientist can determine the DNA's profile. Once the profile is determined, it can be compared to anyone's profile.
• [The Polymerase Chain Reaction (“PCR”)] method, through which small DNA samples can be “amplified” in order to permit testing, has passed general muster in Indiana for scientific reliability and admissibility in evidence at trial.
• In simplified terms, [a newer method, Short Tandem Repeat (“STR”) analysis,] provides a more statistically reliable result by comparing more loci among the huge number comprising a strand of one human's DNA with that of another.
• [W]e conclude that the trial court was well within its discretion in finding the scientific principles of STR testing to be reliable and generally accepted in the relevant scientific community.
See Overstreet v. State, 783 N.E.2d 1140, 1150 (Ind. 2003), cert. denied, 540 U.S. 1150 (2004)(citing Troxell v. State, 778 N.E.2d 811, 815-16 (Ind. 2002))(“In Troxell, this court found that STR testing is generally regarded as reliable as both the scientific literature and a multitude of state courts have similarly concluded.”)
Admissibility: In general
• It is well established that there is no inherent bar to the admission of DNA evidence in criminal prosecutions.
• [But] [t]he phrase “DNA test results” is not a magic one that “‘once uttered, cause[s] the doors of admissibility to open.’”
See Troxell v. State, 778 N.E.2d 811, 815 (Ind. 2002)(quoting Smith v. State, 702 N.E.2d 668, 672 (Ind. 1998))(“This Court has noted that ‘the words ‘DNA test results' are not magic words which, once uttered, cause the doors of admissibility to open.’”)
• The results of DNA testing, like any other evidence aided by expert testimony, must be offered in conformity with the Indiana Rules of Evidence.
See Kennedy v. State, 934 N.E.2d 779, 785 (Ind. Ct. App. 2010)(citing Smith v. State, 702 N.E.2d 668, 672 (Ind. 1998))(“Rather . . . DNA evidence presented by expert testimony must satisfy the requirements of the Indiana Rules of Evidence, including Rule 702.”)
• For information about testimony by expert witnesses, please review ?.
• DNA testing is admissible if the trial court is satisfied that: (1) the scientific principles upon which the expert testimony rests are reliable; (2) the witness is qualified; and (3) the testimony's probative value is not substantially outweighed by the dangers of unfair prejudice.
Overstreet v. State, 783 N.E.2d 1140, 1150 (Ind. 2003), cert. denied, 540 U.S. 1150 (2004)(quoting Ingram v. State, 699 N.E.2d 261, 262 (Ind. 1998))(“Accordingly, DNA testimony becomes admissible as evidence when the trial court is satisfied that: ‘(1) the scientific principles upon which the expert testimony rests are reliable; (2) the witness is qualified; and (3) the testimony's probative value is not substantially outweighed by the dangers of unfair prejudice.’”)
• For information about the reliability and admissibility of scientific evidence, please review Scientific Evidence.
• For information about the qualifications of witnesses, please review Witnesses.
• DNA evidence is admissible in Indiana when the DNA analysis indicates a defendant's profile is consistent with DNA found at the crime scene because such evidence has high probative value.
• DNA evidence that does not constitute a match or is not accompanied by statistical data regarding the probability of a defendant's contribution to a mixed sample is not relevant, Evid. R. 402, and should not be admitted.
• Without statistical data, evidence of a non-match is meaningless, and does not assist the trier of fact in determining the guilt or innocence of the defendant, as required for admissibility of the DNA evidence under Evid. R. 401 and expert testimony thereon under Evid. R. 702.
Admissibility: Effect of IC 35-37-4-13(b)
• In a criminal trial or hearing, the results of forensic DNA analysis are admissible in evidence without antecedent expert testimony that forensic DNA analysis provides a trustworthy and reliable method of identifying characteristics in an individual's genetic material.
• Although IC 35-37-4-13(b), enacted in 1991, attempted to make DNA evidence per se admissible without an inquiry into whether it is scientifically reliable in a particular case, Harrison v. State, 644 N.E.2d 1243, 1251 n. 14 (Ind. 1995), held that DNA testing, like any other evidence aided by expert testimony, must be offered in conformity with the Indiana Rules of Evidence.
See Smith v. State, 702 N.E.2d 668, 672 (Ind. 1998)(“Like any other evidence, and notwithstanding Indiana Code section 35-37-4-13(b), DNA evidence presented by expert testimony must satisfy the requirements of the Indiana Rules of Evidence.”)
As direct and circumstantial evidence: In general
• The DNA evidence in this case was direct evidence only of the defendant's presence with the victim at some prior time, but only circumstantial as to the defendant's criminal conduct and requisite intent as to each of the charged crimes.
• DNA evidence may not always be circumstantial. For example, if the victim were legally incapable of consent, such as a “child under fourteen years of age,” the same type of DNA evidence offered in this case may be direct evidence of the actus reas [sic] for statutory rape.
As direct and circumstantial evidence: Inferences that can be drawn from DNA
• Like a fingerprint, DNA is a marker of identity.
• For information about the inferences that can be drawn from fingerprints, please review Fingerprints.
• For more information about fingerprints, including the admissibility of fingerprints, please review Fingerprints.
• [The defendant’s] jury could have found the glove containing [the defendant’s] DNA, together with other evidence offered by the State, to be sufficient proof of [the defendant’s] identity as the burglar.
Relationship to searches and seizures
• [I]t is clear that DNA tests are searches under the Fourth Amendment.
• We have previously held the taking of a biological sample, such as a DNA sample, constitutes a “search” for purposes of the Fourth Amendment. Therefore, the compulsory collection of a DNA sample to be included in the Indiana DNA Database must comport with the Fourth Amendment.
• We agree with several courts that have held that, once DNA is used to create a profile, the profile becomes the property of the Crime Lab. Thus, [the defendant] had no possessory or ownership interest in it. Nor does society recognize an expectation of privacy in records made for public purposes from legitimately obtained samples. As the Court of Appeals pointed out, courts from other jurisdictions have held that the comparison of a DNA profile with other DNA evidence from a database does not violate the Fourth Amendment. We agree.
• [W]e again observe that [the defendant’s] DNA profile was submitted to the Indiana DNA database in 2003 following his conviction for burglary. Since that time, there has been no seizure or invasion of [the defendant’s] privacy for which a warrant or probable cause was required. While [the defendant] had a legitimate expectation of privacy in his DNA sample at the time it was taken in 2003, he litigated that issue in that particular proceeding. And, as our Supreme Court recognized in Smith, once DNA is used to create a profile, the individual has no possessory or ownership interest in it.