DNA Extraction from Meat Samples

DNA was extracted from meat samples by phenol/chloroform extraction [16 (link)]. All samples (100 mg) were mixed with 800 μl histiocyte lysis buffer (TIANGEN Biotech, Beijing, China) and 100 μg proteinase K (TIANGEN Biotech, Beijing, China). Following 60 min incubation at 65°C with occasional vigorous shaking, an equal volume of phenol/chloroform was added; samples were mixed and centrifuged at 12,000 rpm for 10 min. The resulting supernatant was collected, and an equal volume of chloroform was added; samples were mixed and centrifuged at 12,000 rpm for 5 min. The aqueous layer was transferred to a clean tube. An equal volume of ice-cold 100% EtOH and a one-tenth volume of 3M sodium acetate (pH 5.2) were added; samples were mixed incubated at -20°C for 30 min, and centrifuged at 12,000 rpm for 30 min. The supernatant was discarded and the pellet was washed twice with 800 μl 75% EtOH. Following centrifugation at 12,000 rpm for 5 min, the pellet was air-dried and resuspended in 100 μl DNAse-free and RNAse-free water (Invitrogen, Carlsbad, CA, USA). The DNA concentration of each sample was measured in a NanoVue spectrophotometer (GE Healthcare China, Beijing, China).