Co-amplification of microbial DNA: A novel observation of a misconstrued second peak at locus D7S820

DNA fingerprinting, a gold standard, is one of the most powerful tool in applied sciences especially helpful in criminal investigation. Entering in advanced era of forensic DNA, profile reading is much trickier than ever. An unusual DNA profile was observed from a nail swab of female brutally murdered in a domestic violence case. At first, DNA profile was misconstrued as heterozygote at locus D7S820 but later, it was confirmed as homozygous from other evidence items submitted in the same case. Subsequent reprocessing of the same sample, from the extraction stage through to DNA profiling and DNA profile form victim's blood, conclusively established that the unusual peak is from a non-specific microbial presence at that locus.