**3.2. Sample collection, storage, and characterization for DNA analysis**

Nowadays, whole blood is considered to be the most widely used source of DNA. It is harvested on anticoagulant EDTA (ethylenediaminetetraacetic acid). It can be conserved at 4°C for a maximum of 5–7 days; after this time, the DNA sample being kept at -20°C for a few weeks, or at -80°C for longer periods of time [7].

In the case of blood harvested during autopsy, it does not need anticoagulant and it can be harvested from the following organs:

**•** Heart chambers;


Apart from whole blood, epithelial cells from oral mucosa as well as hair are considered to be important sources for DNA analysis, being frequently used. In the case of epithelial cells, they are harvested with a sterile bud or brush. After harvesting, they are wrapped in a paper envelope and put to dry. Hair is taken by pulling, 5–10 with the root being enough for the analysis.

The hair is wrapped in paper envelopes or plastic wrapping and is kept in a dry environment, at room temperature [8].

In comparison with the biological samples mentioned earlier, in the case of tissue, muscles, organs, or skin, the harvested volume needs to be between 2 and 4 cm. Right after harvesting, the DNA extraction and isolation follows because both its quantity and quality decrease in time and depend on the storage conditions.
