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March 21, 2003


The opinion of the court was delivered by: Garrett E. Brown, Jr., United States District Judge


This matter comes before the Court upon defendant Carlton Ewell's motion for a new trial regarding the Court's admission of the Government's DNA evidence at trial. For the reasons discussed below, defendant's motion is denied and the following findings and conclusions shall hereby supplement the Court's November 15, 2002 Order denying the defendants' motion to suppress the Government's DNA evidence and granting the Government's motion to admit the DNA evidence.

I. FACTS*fn1

On April 25, April 26, and August 13, 2002, the Court held a Daubert*fn2 hearing regarding the admissibility of the Government's DNA evidence.*fn3 There the Court heard testimony from the Government's expert, Dr. Bruce Budowle, and defense expert Dr. Theodore Kessis. Based upon the testimony and the parties' submissions the Court makes the following findings.

A. Testifying Experts

1. Dr. Bruce Budowle

Dr. Budowle, the Government's expert at the Daubert hearing, is a Senior Scientist in the FBI Laboratory Division, Washington, D.C. 1T12. In nineteen years with the FBI, Dr. Budowle has been the unit chief of the FBI Research Unit and the program manager of the DNA Research Group as well as a research chemist. Id. Dr. Budowle holds a doctorate in genetics from Virginia Polytechnic and State University, and completed a postdoctoral fellowship at the University of Alabama. Id. at 13.

Dr. Budowle served as the chair of the Technical Working Group for DNA Analysis Methods, the chair of the International Society of Forensic Genetics DNA Commission, and the federal DNA Advisory Board. Id. at 14. In addition, Dr. Budowle has published approximately 300 publications in the field of genetics, forensic DNA analysis and molecular biology.*fn4 Id. at 15. Dr. Budowle has worked first-hand with all stages of the forensic DNA analysis process, including extracting samples, RFLP typing, PCR amplification, sequencing, population genetic research and validation testing. Id. at 17.

2. Dr. Theodore Kessis

The defense expert, Dr. Kessis, is a self-employed consultant operating a business known as Applied DNA Resources. 3T3. Dr. Kessis holds a doctorate in molecular biology from the Johns Hopkins University School of Public Health in Baltimore and was post-doctoral fellow at Hopkins in the School of Medicine, Department of Pathology. Id at 4. Dr. Kessis has been published approximately 20 times in peer reviewed journals. Id. The majority of his published materials relate to PCR DNA testing, although only two of his articles specifically relate to PCR-STR DNA typing. Id. at 4, 6. Dr. Kessis has been accepted as a DNA expert in several prior cases, but he has never been deemed to be an expert in PCR/STR technology. Id. at 5, 7. Dr. Kessis was admitted here as an expert in PCR, DNA and molecular biology. Id. at 8.

B. Basic Concepts of DNA

The following overview of the basic concepts of DNA, quoted from United States v. Shea, 957 F. Supp. 331, 333 (D.N.H. 1997), aff'd, 159 F.3d 37 (1998), cert. denied, 526 U.S. 1077 (1999), is in accord with the testimony of the instant experts:*fn5

DNA, an acronym for deoxyribonucleic acid, is the chemical blueprint for life. Most human cells other than reproductive cells contain identical copies of a person's DNA. Although 99.9% of human DNA does not vary from person to person, no two persons other than identical twins have the same DNA. (citation omitted).
Human DNA is organized into 23 pairs of chromosomes and each chromosome contains a DNA molecule. DNA molecules have a double stranded helical structure that can be envisioned as a spiral staircase. (citation omitted). Running between the two sugar — phosphate strands forming the handrails of the staircase are millions of steps comprised of two loosely bound nitrogen bases. Each step is referred to as a base pair. There are four types of bases: adenine (A), thymine (T), guanine (G), and cytosine (C). A's ordinarily pair only with T's, and C's ordinarily pair only with G's. Thus, if the sequence of bases on one side of a DNA molecule is known, the corresponding sequence of bases on the other side can be deduced. The arrangement of base pairs in chromosomal DNA comprises the genetic code that differentiates humans from non-humans and makes every person unique. (citation omitted).

In total, the DNA molecules in the 23 pairs of human chromosomes contain approximately 3.3 billion base pairs. Most of the base pairs are arranged in the same sequence in all humans. (citation omitted). However, every DNA molecule has regions known as polymorphic sites where variability is found in the human population. (footnote omitted). Each possible arrangement of base pairs that occurs at a polymorphic site is referred to as an allele. Alleles can result from differences in a single base pair, differences in multiple base pairs, or differences in the number of base pairs that comprise a site.

The combination of alleles from corresponding sites on a chromosome pair is sometimes referred to as the site's genotype. (footnote and citation omitted). One allele for each single locus genotype is inherited from each parent. If both parents contribute the same type of allele, the child's genotype is considered to be homozygous. If each parent contributes a different type of allele, the child's genotype is considered to be heterozygous. To illustrate, if only two alleles for a locus are found in the population, A and a, two homozygous genotypes, AA and aa, and one heterozygous genotype, Aa, will be found in the population. Although an individual's genotype consists of either two copies of the same allele or one copy of each of two different alleles, many different alleles may be found in the population for a single locus. (citation omitted).

C. PCR/STR DNA Analysis*fn6

Because there is no way to sequence and compare all 3 billion base pairs in a person's DNA, forensic DNA analysts seek to identify individuals through meaningful variations in their base-pair sequences at particular polymorphic loci. The method of DNA typing employed by the FBI laboratory in the instant matter is commonly referred to as PCR/STR typing.

1. Basic Concepts of PCR Amplification

PCR/STR typing begins with the PCR amplification process. PCR is not itself a method of DNA typing, but a technique of sample preparation. 1T34. PCR is a laboratory process for copying a short segment of DNA millions of times, thereby replicating the natural DNA duplication process. Id. This process allows labs to produce a substantial number of specific, targeted segments of DNA which exhibit genetic variation that can then be typed and compared from an original sample that may have been of a subanalytical quality. Id. The principle benefit of the PCR process is that it enables the forensic analysis of very tiny amounts of DNA. Id. at 33.

The PCR process has three steps. First, the double-stranded segment of DNA is separated into two strands by heating. Id. Because the bases along the DNA strand are always found in complimentary pairs, a heat-separated DNA strand forms a template that can allow the manufacture of a new strand identical to its former complimentary strand.

In the second step, each of the single strand segments are hybridized with short DNA segments known as primers, that are designed to bind with the single strand segments at particular loci. Id. at 34-35. The primers are designed to compliment a sequence just outside of a target sequence of bases.

Lastly, each primer is the starting point for the replication of the target sequence. In the third step an enzyme known as a polymerase becomes active. The polymerase facilitates repeated additions of bases to the primer until a new complimentary strand of the targeted DNA locus is created. Id. at 37. Thus, the PCR process replicates the initial double stranded molecule into two copies.

The PCR process is repeated a number of times, thereby creating an exponentially increasing number of copies of the targeted area of the original DNA. After about thirty repeated cycles, millions of copies of the particular target sequence are created by the laboratory. To minimize the chance of human error and contamination, the laboratory can use a process called multiplexing. Id. at 40-41. Multiplexing allows the laboratory to type the DNA sample at multiple sites by adding additional primers which will bind simultaneously to their respective target sites. Id. at 39.

2. Short Tandem Repeats — STR Analysis

A tandem repeat involves multiple copies of an identical DNA sequence arranged in direct succession in a particular region of a chromosome. A short tandem repeat ("STR") is a tandem repeat in which the core base units are just a few base pairs. Id. at 42. Loci containing ...

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