MATERIAL AND METHODSMaterial. Papay

MATERIAL AND METHODS

Material. Papaya samples were collected on the market. The fruit was peeled, the flesh was separated from the stones, cut into pieces and the slices of papaya flesh was dried in the oven at 37°C for 12 h to reduce the moisture content. Both the tissue were stored at –80°C until further processed.

The candied papaya was stored at room tem-perature until processed.
DNA isolation. From each sample two inde-pendent isolations were performed. Prior to DNA isolation, samples were homogenised in liquid nitrogen.

CTAB based DNA extraction. CTAB method (Cetyl trimethylammonium bromide) DNA isolota-tion was performed according ISO Standard (EN ISO 21571:2002). Total of 200 mg of powdered sample was used for DNA isolation. Extracted DNAs were eluted in 60 µl of 0.1 × TE buffer.

Wizard DNA extraction. DNAs were extracted and purified using the modified Wizard method. 200 mg of powdered sample was mixed with 860 µl of TNE buffer (5mM Tris-HCl, pH 8.0, 2mM EDTA, 150mM NaCl, 1% SDS). The mixture was vortexed. 100 µl of 5M guanidin hydrochloride and 40 µl of proteinase K hydrochloride were added to the solution, the mixture was vortexed and after that incubated at 58°C for 5 hours with occassionaly mix-ing. After incubation, the mixture was centrifuged for 10 min at 13 000 × g. 500 µl of supernatant was transferred into the new microtube and 10 µl of RNase was added to the sample. The sample was further incubated at 65°C for 10 minutes. DNA solu-tion was subsequently purified with Wizard DNA Clean-Up System (Promega, Madison, USA).

GeneSpin DNA Isolation Kit. DNA was extracted using GeneSpin DNA Extraction Kit (Eurofins, Freiburg, Germany) following the manufacturers instructions. Total of 200 mg of powdered sample was used. In the case of candied papaya the pro-tocol was modified as follows. The volume of lysis buffer increased to 700 µl and time of incubation was prolonged to 1 hour.

Assessment of DNA quality. DNAs were evalu-ated by agarose electrophoresis for its integrity and raugh estimation of quantity. For detailed


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