Differentiating between monozygotic twins through DNA methylation specific high resolution melt curve analysis

Although STR profiling is extremely powerful in identifying individuals from crime scene stains, it is unable to differentiate between monozygotic (MZ) twins. Efforts to address this include mutation analysis through whole genome sequencing and through DNA methylation studies. Methylation of DNA is affected by environmental factors; thus, as MZ twins age, their DNA methylation patterns change. This can be characterised by bi-sulfite treatment followed by pyrosequencing. However, this can be time consuming and expensive, thus unlikely to be widely used by investigators. If the sequences are different, then, in theory, the melting temperature should be different. Thus the aim of this study is to assess whether high resolution melt curve analysis can be used to differentiate between MZ twins. Five sets of MZ twins provided buccal swabs which underwent extraction, quantification, bi-sulfite treatment, PCR amplification and high resolution melting curve analysis targeting two markers, Alu-E2F3 and Alu-SP. Significant differences were observed between all MZ twins, targeting Alu-E2F3, and in four out of five MZ twins, targeting Alu-SP (p<0.05). Thus it has been demonstrated that bi-sulfite treatment followed by high resolution melting curve analysis could be used to differentiate between MZ twins.