Date of Submission

5-2019

Document Type

Thesis

Degree Name

Master of Science in Forensic Science

Department

Forensic Science

Advisor

Timothy Palmbach

Committee Member

Claire Glynn

Committee Member

Lisa McEwen

MeSH

DNA Methylation

LCSH

Human trafficking, Child trafficking victims, Child trafficking--Investigation, Child labor

Abstract

The International Labor Organization (ILO) estimated over 30 million individuals fall victim to human trafficking each year, of which, 50% are children below the age of 16. In 2012, the ILO reported there to be 168 million child laborers worldwide, with many trafficked into hazardous conditions to manufacture consumer products that are sold in developed countries. This is a modern form of slavery with poor working conditions, no access to education, and low wages. The hidden nature of this crime, however, makes it extremely difficult to identify and locate victims of forced child labor, and thus making it challenging to eradicate.

Children exploited in textile factories typically handle fabrics with bare hands, causing them to shed epithelial cells that contain DNA onto items they are manufacturing. It has been established that touch DNA can be isolated from a variety of substrates, which has the potential to be used to estimate the chronological age of an individual that handled the fabric. DNA methylation is an epigenetic modification which adds a methyl group to the nitrogenous base, cytosine, which can be involved in the regulation of gene expression. Previous research has determined that children have differentially methylated sites in their DNA that can be used as markers to estimate chronological age.

To establish that current procedures could identify DNA from child laborers, touch samples were collected from sixty-seven volunteers within the age range of 0-65 years old on sterile gauze swatches following IRB approval. Total DNA was isolated from the gauze using the DNA Investigator Kit and bisulfite converted using the Qigen EpiTect BC Kit. Samples were quantified using the Qubit® 3 Fluorometer. In addition, some samples were quantified using the Human Quantifiler Kit. Custom primers and TaqMan Probes were designed for several age-associated methylation sites. Two different methylation qPCR kits were attempted for this assay - the EpiTect MethyLight + ROX Kit and the Methylamp MS-qPCR Fast Kit. Both qPCR assays were unsuccessful at quantifying DNA methylation from touch samples due to the low quantity of original DNA (average 0.092ng/μl). This study makes is clear that touch DNA is extremely difficult to collect in large enough quantities that can be used for downstream analysis.

There is an apparent need for improved touch DNA collection methods. In addition, increased sensitivity of methylation quantification could contribute to optimizing this methodology for future use in chronological age estimation and subsequently identify manufacturers that are exploiting child laborers.

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