Date of Award
Summer 8-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department/Program
Forensic Science
Language
English
First Advisor or Mentor
Lissette Delgado-Cruzata
Second Reader
Marta Concheiro-Guisan
Third Advisor
Sai Casado-Zapico
Abstract
Monozygotic (MZ) twins have identical DNA, making traditional profiling methods insufficient in their discrimination. However, MZ twins can be differentiated by their levels of DNA methylation. Our research group previously developed a methodology to detect cg18562578 DNA methylation levels in MZ twins based on a two- step PCR approach and a cg18562578 MethylQuant Assay. That study generated data for only 64% of the samples it investigated, and showed a discrimination power of 77% to discriminate between MZ twins. Here, we used the same methodology but a different approach to determine DNA methylation in 73 previously unsuccessful twin pairs. We diluted the nested PCR less, 1:500 instead of 1:1000, and used a QuantStudio 96-well instead of a ViiA 7 384-well plate qPCR set up. Data was generated for 82% of the pairs in the sample. We found that there was no difference between MZ and dizygotic (DZ) DNA methylation pair ratios (MZ 0.80±1.2 vs DZ 0.73±0.53, p-value=0.246). However, there were within pair DNA methylation differences for MZ (0.30±0.46 vs 1.10±1.45, p< 0.00001) and DZ twins (0.13±0.12 vs 0.86±0.54, p=0.00012). Differences between MZ twins DNA methylation for differential ratios were lower than 0.1 (0.04±0.05 vs 0.09±0.05, p=0.03), suggesting the approach used here increases the discrimination ability of the assay from 77% to 100%.
Recommended Citation
Chauca, Amber P., "cg18562578 MethylQuant Assay for the Discrimination of Monozygotic Twins" (2025). CUNY Academic Works.
https://academicworks.cuny.edu/jj_etds/361
