Date of Completion

3-14-2013

Embargo Period

3-14-2013

Keywords

mitochondrial DNA, forensic DNA typing, human identification, African Americans, power of discrimination, Mitochip, DNA fingerprinting, mtDNA hypervariable region, molecular genetics, haplogroups, haplotype, SNP

Major Advisor

Linda D. Strausbaugh, Ph.D.

Associate Advisor

Kent Holsinger, Ph.D.

Associate Advisor

Rachel O'Neill, Ph.D.

Field of Study

Genetics and Genomics

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Evaluation of Mitochondrial DNA Typing in a Forensically Relevant Population of Self-Identified U.S. African Americans

Ranyelle S. Reid

University of Connecticut, 2013

Abstract


Analyses of hypervariable segments of mitochondrial DNA (mtDNA) are currently

being used for forensic analysis, human molecular genetics, evolutionary biology,

human migration studies and recovery operations in identifying deceased persons,

both ancient and modern. Mitochondrial DNA analysis offers a unique maternal

ancestral view of an individual’s molecular pin code, through typically examining

the hypervariable segments and sampling the areas of hypervariable region 1

(HV1) and hypervariable region 2 (HV2). The goal of this project is to revisit the

utility of mtDNA typing in forensics through the analysis of a forensically relevant

population of self-identified U.S. African Americans. In Chapter 2, we asked

whether a similarly low level of resolution of HV1 sequence types in Europeans

mtDNA occurred in persons of ‘recent’ African ancestry. Our studies yielded

remarkable variation within the mtgenomes of U.S. African Americans and,

furthermore, demonstrated that mtDNA analysis, in fact, has a higher power of

discrimination when applied to the U.S. African American population (n= 185); a

group inadequately represented in mtDNA databases. Chapter 3 describes our

efforts in the employment of recent advances in DNA typing technologies

(microarray whole genome sequencing, SNP panels) to demonstrate that the

mtDNA-coding region increases the resolving power of mitochondrial DNA forensic

typing. We used whole genome resequencing to identify diagnostic SNPs (mtDNA

variants) that would yield powerful genetic markers into refining the relationship

between ethnicity and haplogroup association. Chapter 4 data illustrate that a clear

majority (90%) of our samples showed concordance between self-identified

ethnicity and haplogroup assignment. In the instances of ethnicity-haplogroup

disagreement, we further evaluated the sample using the diagnostic SNP panel,

which revealed a more accurate reflection of deep ancestry, thereby reclassifying

the haplogroup and establishing concordance between the self-identified ethnicity

and the haplogroup assignment. The findings of this research: improve upon the

current state of knowledge of mtDNA variation in a forensically relevant population

of U.S. African Americans demonstrate that the power of discrimination of mtDNA

HVI typing will vary based on maternal lineage; suggest that HVI typing may be

sufficient for the exclusion of U.S. African Americans; and bolster previous reports

that suggest mtDNA analysis may provide new avenues for the consideration of

alternative or weak suspects.

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