Description
QIAGEN Genomic-tips are gravity-flow, anion-exchange tips that allow efficient purification of genomic DNA from a wide range of biological samples. The purified DNA is sized up to 150 kb with an average size of 50–100 kb
The QIAGEN Genomic-tip procedure is very gentle and results in negligible DNA shearing. DNA purified with QIAGEN Genomic-tips is sized up to 150 kb with an average length of 50–100 kb (see figure "Genomic DNA of up to 150 kb"). The DNA is free of all contaminants such as RNA, protein and metabolites and has A 260 / A 280 ratios between 1.7 and 1.9. QIAGEN Genomic-tips come in a range of sizes to suit every preparation need and are supplied with a comprehensive handbook containing detailed protocols for genomic DNA preparation from each sample type. Specific lysis buffers for blood, tissue, cultured cells, yeast and bacteria and all other necessary buffers are provided in the Genomic DNA Buffer Set which can be purchased separately. Purified DNA has been used in direct bacterial-genome sequencing (see figure "Direct sequencing of bacterial genomic DNA"). QIAGEN Genomic-tip specifications Sample source Amount Yield (µg) Genomic-tip 20/G Genomic-tip 100/G Genomic-tip 500/G Genomic-tip 20/G Genomic-tip 100/G Genomic-tip 500/G Whole blood (human) 1 ml 5 ml 20 ml 15–20 80–100 350–400 Cultured cells (HeLa) 5 x 10 6 2 x 10 7 1 x 10 8 15–20 80–100 350–450 Tissue (liver) 15 mg 80 mg 350 mg 15–20 80–100 350–450 Yeast (S. cerevisiae) 1 ml 5 ml 20 ml 18–20 85–95 350–450 Gram– bacteria (E. coli) 0.6–1.2 ml 3–6 ml 15–30 ml 16–20 85–95 300–400 Gram+ bacteria (B. subtilis) 1.2–1.8 ml 6–9 ml 30–45 ml 16–20 85–95 300–400
QIAGEN Genomic-tips use unique QIAGEN anion-exchange technology for high-molecular-weight DNA isolation from a wide range of biological samples without phenol or chloroform. Lysis buffers are optimized for different sample types and provide immediate denaturation of proteins such as nucleases, histones and DNA-binding proteins, as well as potentially infectious viral particles. Under the pH and low-salt conditions provided by the buffer, DNA binds to the QIAGEN Resin in the column. At the same time, other cell constituents such as proteins, carbohydrates and metabolites flow through. Purified DNA is eluted in high-salt buffer. Genomic-tips operate by gravity flow, and can be left unattended without running dry. This reduces hands-on time to a minimum and makes the procedure ideal for simultaneous processing of multiple samples.
Samples are first lysed (tissue samples are mechanically disrupted) and proteins simultaneously denatured in the appropriate lysis buffer (see flowchart "QIAGEN Genomic-tip procedure"). QIAGEN Protease or Proteinase K is then added and after a suitable incubation period, lysates are loaded onto the QIAGEN Genomic-tip. DNA binds to the column while other cell constituents pass through. Following a wash step to remove any remaining contaminants, pure, high-molecular-weight DNA is eluted and precipitated with isopropanol. Hands-on time for the complete procedure is just 20 minutes for bacteria, 30 minutes for blood and cultured cells and 40 minutes for tissue and yeast.
