PURPOSE: Methods to isolate cell-free fetal DNA from maternal plasma are critical in developing noninvasive fetal DNA testing strategies. Given that plasma consists of heterogeneous DNA-size fragments in a complex mix of proteins, recovery and analysis of this DNA are understandably inefficient. To facilitate recovery, we performed qualitative and quantitative analysis of DNA isolated from maternal plasma. METHODS: DNA isolated from maternal blood (n = 15) was compared using five different DNA isolation protocols: two conventional, two column-based, and one magnetic-bead based. Purity and concentration of DNA recovered were determined with a NanoDrop spectrophotometer. Real-time polymerase chain reaction quantification of the beta-globin and DYS1 loci was performed to determine total and fetal-specific genome equivalents, respectively. RESULTS: DNA quality and quantity were different among the five methods tested. Although purity and concentration of total DNA were greatest with the conventional boiling-lysis approach, correct detection of a male fetus was achieved in only 62.5% of cases. DNA isolation using the magnetic beads yielded the highest quantity of total DNA (2018.83 +/- 4.09 GEq/mL), with 100% fetal DNA detection. CONCLUSIONS: Optimal plasma DNA recovery protocols must take into account DNA purity and concentration. We confirm that the magnetic-beads method provides a fast, simple, sensitive, and specific approach to purify plasma DNA. The resulting high-quality DNA facilitates efficient examination of fetal DNA sequences.
PURPOSE: Methods to isolate cell-free fetal DNA from maternal plasma are critical in developing noninvasive fetal DNA testing strategies. Given that plasma consists of heterogeneous DNA-size fragments in a complex mix of proteins, recovery and analysis of this DNA are understandably inefficient. To facilitate recovery, we performed qualitative and quantitative analysis of DNA isolated from maternal plasma. METHODS: DNA isolated from maternal blood (n = 15) was compared using five different DNA isolation protocols: two conventional, two column-based, and one magnetic-bead based. Purity and concentration of DNA recovered were determined with a NanoDrop spectrophotometer. Real-time polymerase chain reaction quantification of the beta-globin and DYS1 loci was performed to determine total and fetal-specific genome equivalents, respectively. RESULTS: DNA quality and quantity were different among the five methods tested. Although purity and concentration of total DNA were greatest with the conventional boiling-lysis approach, correct detection of a male fetus was achieved in only 62.5% of cases. DNA isolation using the magnetic beads yielded the highest quantity of total DNA (2018.83 +/- 4.09 GEq/mL), with 100% fetal DNA detection. CONCLUSIONS: Optimal plasma DNA recovery protocols must take into account DNA purity and concentration. We confirm that the magnetic-beads method provides a fast, simple, sensitive, and specific approach to purify plasma DNA. The resulting high-quality DNA facilitates efficient examination of fetal DNA sequences.
Authors: Aaron F Orozco; Carolina J Jorgez; Cassandra Horne; Deborah A Marquez-Do; Matthew R Chapman; John R Rodgers; Farideh Z Bischoff; Dorothy E Lewis Journal: Am J Pathol Date: 2008-10-30 Impact factor: 4.307
Authors: Sarah A Ware; Nikita Desai; Mabel Lopez; Daniel Leach; Yingze Zhang; Luca Giordano; Mehdi Nouraie; Martin Picard; Brett A Kaufman Journal: J Biol Chem Date: 2020-09-08 Impact factor: 5.157