Evaluation of nucleosome forming potentials (NFPs) of forensically important STRs

Degraded forensic samples have proved difficult to analyze and interpret. New analysis techniques are constantly being discovered and improved but researchers have overlooked the structural properties that could prevent or slow the process of degradation. In theory, DNA that are bound to histones as nucleosomes are less prone to degradation, because nucleosomes prevent DNA from being exposed to degradative enzymes. In this study we determined the probability of 60 forensic DNA markers to be bound to histones based on their base sequence composition. Two web-based tools – NXSensor and nuScore – were used to analyze four hundred base pairs surrounding each DNA marker for properties that inhibit or promote the binding of DNA to histones. Our results showed that the majority of markers analyzed were likely to be bound as nucleosomes. Selection of the markers that are more protected to form a multiplex could increase the chance of obtaining a better balanced, easier to interpret DNA profile from degraded samples.