4.12DNA (Deoxyribonucleic Acid) Testing and Admissibility¹

“Absent a showing of suppression of evidence, intentional misconduct, or bad faith, the prosecutor and the police are not required to test evidence to accord a defendant due process.” People v Coy, 258 Mich App 1, 21 (2003). Therefore, defendant’s general “complaint that police conducted no forensic testing of the evidence was a matter for the jury to consider in its evaluation of the weight and strength of the evidence, but it [did] not render the evidence presented insufficient to support [the defendant’s] convictions.” People v Savage, 327 Mich App 604, 615 (2019).

A.DNA Molecule Defined

“The [DNA] molecule is a double helix, shaped like a twisted ladder. Phosphate and deoxyribose sugar form the rails of the ladder. Four chemical bases—Adenine (A), Cytosine (C), Guanine (G), and Thymine (T)—lie next to each other on the sugar links along the sides of the ladder. Each A always bonds with a T on the other side of the ladder, and each C always bonds with a G on the other side of the ladder, so that the possible base pairs on the ladder are A-T, T-A, C-G, and G-C. The base pairs are connected by a hydrogen bond, such that the bonds form the rungs of the ladder. There are approximately three billion base pairs in one DNA molecule. Although no two human beings have the same sequence of base pairs (except for identical twins), we share many sequences that create common characteristics such as arms, legs, fingers, and toes. The sequences of variation from person to person are known as polymorphisms. They contain different alleles, which are alternate forms of a gene capable of occupying a single location on a chromosome. Polymorphisms are the key to DNA identification because they create the individual characteristics of everyone and are detectable in laboratory testing.”People v Adams, 195 Mich App 267, 270 (1992), modified and remanded on other grounds 441 Mich 916 (1993).²

B.Mitochondrial DNA (mtDNA)

Mitochondrial DNA testing is admissible without a Davis-Frye³ hearing. People v Holtzer, 255 Mich App 478, 488 (2003). The Holtzer Court explained the differences between mtDNA and nuclear DNA:

“There are two types of DNA, nuclear DNA (nDNA) and mitochondrial DNA [(mtDNA)]. Every cell of the body, except for red blood cells, contains both types of DNA. Nuclear DNA is the more commonly known variety, and is found in the nucleus of the cell. One-half of an individual’s nuclear DNA comes from each parent. Each nDNA molecule consists of approximately three billion base pairs of nucleotides. Although over ninety-nine percent of nuclear DNA is the same for all people, every person, except for identical twins, has unique differences in his nuclear DNA. It is this uniqueness that gives rise to its usefulness in forensic work.

Mitochondrial DNA, on the other hand, is found in small organelles called mitochondria, which are found in every cell floating in the protoplasm. An mtDNA molecule is significantly smaller than an nDNA molecule, containing only about sixteen thousand base pairs. It also differs from nDNA in that mtDNA is inherited solely from the mother. Accordingly, it can be used to establish a maternal lineage. Another difference between nDNA and mtDNA is that nDNA is arranged in a long, double helix ‘twisted ladder’ formation while mtDNA has a circular formation, like a twisted rubber band. Furthermore, while each cell has only one nucleus, it may have thousands of copies of mitochondria, and each mitochondria has between two and ten copies of mtDNA. Thus, while nDNA is significantly larger in size, mtDNA is present in significantly greater numbers. Additionally, mtDNA is more likely than nDNA to survive in a dead cell. Thus, it is easier to recover useable mtDNA than usable nDNA.” Holtzer, 255 Mich App at 481-482.

C.Methods of Testing DNA

Any question about whether laboratory procedures were properly followed in testing DNA evidence presents an issue of weight, not admissibility, and is a question to be determined by the jury. People Holtzer, 255 Mich App 478, 490 (2003).

1.Restriction Fragment Length Polymorphisms (RFLP) Method

DNA identification testing does not require a Davis-Frye⁴ hearing for its admissibility because “DNA identification testing is generally accepted in the scientific community as reliable.” People v Adams, 195 Mich App 267, 277 (1992), modified and remanded on other grounds 441 Mich 916 (1993)⁵ (DNA testing was performed using the RFLP method on dried semen found on the victim’s blue jeans). Because of the overall acceptance of DNA testing in other jurisdictions, a trial court may take judicial notice of DNA identification testing’s reliability. Adams, 195 Mich App at 277. However, the prosecution must show that the laboratory performing the DNA testing followed the generally accepted laboratory procedures before the DNA test results are admitted into evidence. Id.

See also People v Leonard, 224 Mich App 569, 589-591 (1997) (DNA results obtained by use of the RFLP method were properly admitted at trial because “[t]he RFLP method of DNA testing has been already established as accepted on the scientific community”).

2.Polymerase Chain Reaction (PCR) Method

A Davis-Frye⁶ hearing is not necessary to show the general acceptance of PCR (polymerase chain reaction) DNA testing methods within the scientific community. People v Coy, 258 Mich App 1, 9-12 (2003).

DNA identification evidence using the PCR method was properly admitted at trial because the method met the Davis-Frye standard for admission. People v Lee, 212 Mich App 228, 281-282 (1995). As with People v Adams, 195 Mich App 267, 277 (1992), modified and remanded on other grounds 441 Mich 916 (1993)⁷, before the DNA identification evidence is admitted, the prosecution must show that the laboratory conducting the DNA test employed generally accepted procedures. Lee, 212 Mich App at 283. See also People v McMillan, 213 Mich App 134, 136-137 (1995) (DNA evidence obtained using the PCR method was properly admitted at trial).

3.STRmix Probabilistic Genotype Method

“STRmix probabilistic genotype testing” is “a more recent form of DNA testing and a relatively new method of evaluating complex mixtures.” People v Muhammad, 326 Mich App 40, 47 (2018). It “is a generally accepted method” of DNA testing. Id. at 56. In Muhammad, “the trial court did not abuse its discretion in concluding that the DNA evidence [interpreted by using STRmix probabilistic genotype testing performed on the shoe of a robbery suspect] was admissible under MRE 702.”⁸ Muhammad, 326 Mich App at 57. “STRmix uses well-established mathematical and scientific methods and . . . the software has undergone various validation studies,” including “manual calculations, true and false donor tests, and tests against other software”; “STRmix has also been validated by four forensic laboratories in the United States and is being validated by other laboratories”; and “STRmix [has been] subjected to peer review and approved for casework by the New York Commission on Forensic Science.” Id.

D.Statistical Interpretation Evidence of DNA Results

“Statistical evidence of DNA is generally admissible”; “statistics are an integral part of DNA evidence and are necessary to assist the trier of fact.” People v Coy (Coy II), 258 Mich App 1, 11 (2003). “The results of DNA identification testing would be a matter of speculation without the statistical analysis[.]” People v Adams, 195 Mich App 267, 279 (1992), modified and remanded on other grounds 441 Mich 916 (1993).⁹ See also People v Coy (Coy I), 243 Mich App 283, 294 (2000) (finding that the evidence of a potential match between a subject’s DNA sample and DNA found on evidence is “inadmissible absent some accompanying interpretive evidence regarding the likelihood of the potential match”). “The Coy standard requires that when DNA evidence is introduced, it must be accompanied by some qualitative or quantitative interpretation. The descriptive phrase, ‘to a reasonable degree of scientific certainty’ offers neither.” People v Urban, 504 Mich 950, 950-951, 951 n 1 (2019) (applying the Coy standard “[b]ecause neither party argue[d that it] should be overruled” and declining to “address whether it is the appropriate standard”) (citation omitted).

“DNA statistical analysis determines the frequency with which a particular match occurs in a target population—how likely or unlikely it is that an individual other than the defendant has the same DNA bands as those found at the crime scene and in [a] defendant’s blood.” People v Chandler, 211 Mich App 604, 608, 611 (1995) (admission of DNA statistical interpretation evidence does not require a Davis-Frye hearing). See also People v Leonard, 224 Mich App 569, 591 (1997) (“statistical evidence need not be subjected to a Davis-Frye test”; “any challenges to the statistical evidence are relevant to the weight of the evidence and not to its admissibility”).

The admission of testimony that there was a “potential match between defendant’s DNA and the DNA contained in the mixed blood samples found on the knife blade and the doorknob” violated MRE 702 and MRE 403 because no analytic or interpretive evidence concerning the likelihood or significance of a DNA profile match was admitted and without testimony explaining the statistical significance of a potential match, the testimony about a potential match did not assist the jury in determining whether the defendant contributed DNA to the mixed sample. Coy I, 243 Mich App at 301-303.

E.Indigent Defendant’s Right to Appointment of DNA Expert

A defendant may be entitled to a court-appointed DNA expert if the defendant can make a particularized showing that there exists a reasonable probability that an expert would be of assistance to the defense and that denial of expert assistance would result in a fundamentally unfair trial. See People v Kennedy, 502 Mich 206, 228 (2018). See Section 4.1(K)(2) for more information on appointing an expert for an indigent defendant.