COURT FOR THE COUNTY OF 
| Chapter 16: Scientific Evidence |
As a general rule DNA evidence is admissible, as long as proper laboratory procedures are followed. People v Adams, 195 Mich App 267 (1992), modified on other grds 441 Mich 916 (1993); People v Courts, 205 Mich App 326 (1994); People v Chandler, 211 Mich App 604 (1995). Statistical evidence is also admissible. People v Leonard, 224 Mich App 569 (1997).
There are two methods of DNA testing, the RFLP method and the PCR method, both of which are generally accepted in the scientific community. People v Chandler, supra. The PCR method is quicker and more widely used. People v Adams, supra. The prosecutor must show that generally accepted scientific procedures were followed, and expert testimony may be considered in determining the weight of PCR evidence. People v Lee (After Remand), 212 Mich App 228 (1995). Statistical analysis is not subject to the Davis/Frye criteria for admissibility of scientific evidence. Challenges to the statistical analysis go to weight, not admissibility. People v Chandler, supra. There has been a continuing controversy in the scientific community over the best method of calculating the probability of a random match. The National Research Council (NRC) recommends use of the "ceiling principle," which is more conservative over the "multiplication rule" or "product rule" method. The "product rule" method was recognized as generally accepted in People v Adams, supra, and People v Chandler, supra. But see State v Streich, 658 A2d 38 (VT, 1995), where the Vermont Supreme Court rejected the product rule.
In the absence of a defense request, the prosecution has no obligation to conduct DNA testing. People v Derrick Vaughn, 200 Mich App 611 (1993), rev'd on other grds 447 Mich 217 (1994).
Challenges may be mounted to the manner in which DNA evidence was collected by police and processed as evidence. Trial attorneys should examine such issues as whether gloves were worn or changed often, whether disposable collection instruments were used, and whether the evidence was stored in paper or plastic bags. Also relevant is whether the test was repeated with the same results, and whether the lab and/or the analyst have been tested for proficiency. New guidelines for police officers have been published by the National Commission on the Future of DNA Evidence, at http://www.ojp.usdoj.gov/nij/pubs.htm.
To prepare to challenge the admissibility of this evidence, and particularly the statistical conclusions drawn from it, you need to look at the data itself, preferably with the assistance of your own expert. Find out whether the lab meets federal standards, or if appropriate procedures were followed. You can challenge both the quality of the evidence itself, as well as the prejudicial effect it will have on your client.
It is doubtful the defense could effectively challenge DNA evidence without an expert. The Alabama Supreme Court has held that whenever the state intends to introduce DNA evidence, the defendant has a due process right to appointment of a DNA expert. Ex Parte State of Alabama (Dubose v State), 662 So2d 1189 (Ala, 1995). The defense is required to show that expert testimony would likely benefit the defense and that there is a nexus between the facts of the case and the need for an expert. MCL 775.15; MSA 28.1252; People v Jacobsen, 448 Mich 639 (1995); People v Leonard, 224 Mich App 569 (1997).
16.1 Motion to Introduce DNA Evidence [Download: WP | Word | PDF]
COURT FOR THE COUNTY OF
____________________________________
PEOPLE OF THE
STATE OF MICHIGAN,
Plaintiff, No. 
vs Hon. 
,
Defendant.
____________________________________/
The Defendant, 
, by 
attorney, moves this Court to allow the introduction of
DNA evidence in this case pursuant to MRE 702 and 703 and the following:
1. The police crime lab testing of the genetic material left at the crime scene excludes 
as
its donor. 
2. While this form of testing cannot identify a donor exactly, it is able to exclude with precision.
3. Since the question in this case is identity of the suspect, this evidence is highly relevant.
4. As a general rule DNA evidence is admissible, as long as proper laboratory procedures are followed. People v Adams, 195 Mich App 267 (1992); People v Chandler, 211 Mich App 604 (1995).
For these reasons, 
asks that this motion be granted and that the results of the DNA
testing be admitted into evidence.
Respectfully submitted,
______________________
Attorney for Defendant
COURT FOR THE COUNTY OF 
____________________________________
PEOPLE OF THE
STATE OF MICHIGAN,
Plaintiff, No. 
vs Hon. 
,
Defendant.
_____________________________________/
The Defendant, 
, by 
attorney, moves this Court to preclude the introduction
of DNA evidence pursuant to MRE 702 and 703 and the following:
1. The prosecution intends to introduce DNA evidence in this case.
2. The prosecution cannot prove that generally accepted laboratory procedures were followed. People v Chandler, 211 Mich App 604 (1995); People v Lee, 212 Mich App 228 (1995).
3. The result of the DNA testing shows that 
cannot be excluded as a suspect in this case.
4. The introduction of this evidence will be through the use of probability statistics.
5. The prosecution expert will testify that 
cannot be excluded as the suspect through DNA
testing and will offer an opinion as to the "odds" that the genetic material is from someone other than
.
6. The expert's testimony will indicate the percentage of the population which share the same allele structure, and then offer an opinion as to what that number is in relation to population estimates from the 1990 census.
7. The expert used the "product rule" method of statistical anaylsis, which has been rejected in some courts. (See State v Streich, 658 A2d 38 (Vt, 1995). The National Research Council recommends use of the "ceiling principle" method, which was not used in this case.
8. These statistics are misleading, and give the false impression to a jury that 
committed
this offense.
9. Expert testimony of this nature will lead the jury inexorably to the conclusion that this test proves that
is the perpetrator, despite the fact that the results of the test only show that he cannot be
excluded as the perpetrator based on the genetic material tested.
10. The evidence is more unfairly prejudicial than probative, MRE 403, and its introduction will deny defendant 
right to due process of law. US Const. Am. XIV; Mich Const. 1963, art. 1 §17.
For these reasons, 
requests that the prosecution be directed not to elicit or refer to in
any way the results of the DNA testing, or in the alternative, 
asks that this court exclude any
statistical testimony regarding the significance of the non-exclusion result.
Respectfully submitted,
______________________
Attorney for Defendant