I-motif DNA I-motif DNA i-motif DNA is a type of deoxyribonucleic acid, discovered in 2018, that is found in the nuclei of human cells. An abbreviation of intercalated motif, the four-strand i-motif is unlike the iconic double helix DNA. I-motifs are four-stranded quadruplex structures formed by cytosine-rich DNA, similar to the G-quadruplex structures that guanine-rich DNA forms. C-rich DNA regions are common in gene regulation portions of the genome. Recently, i-motifs were discovered in human cells and were shown to play a role in cell reproduction. I-motifs have potential applications in nanotechnology and nanomedicine due to their unique pH sensitivity and have
Cell-free fetal DNA with single base specificity and single DNA molecule sensitivity. DNA is amplified by PCR. Then, linear amplification with base extension reaction (with a third primer) is designed to anneal to the region upstream from the mutation site. One or two bases are added to the extension primer to produce two extension products from wild-type DNA and mutant DNA. Single base specificity provides advantages over hybridization-based techniques using TaqMan hydrolysis probes. When assessing the technique, no false positives or negatives were found when looking for cffDNA to determine fetal sex in sixteen maternal plasma samples. The sex of ninety of ninety-one