Final answer:
A buccal swab specimen for DNA testing is collected by rubbing a sterile swab inside a child's cheek, smearing it onto a slide, allowing it to dry, heat fixing, and then safely disposing of the swab. The child's DNA must share genetic markers with both suspected parents to confirm a biological relationship.
Step-by-step explanation:
To collect a buccal swab specimen from a child's mouth for DNA testing, certain steps need to be carefully followed. Initially, a prepared slide should be obtained along with a sterile swab. The actual process involves gently rubbing the swab inside the child's cheek to collect a sample of the oral mucosa. After obtaining the sample, it is critical to evenly smear the swab over the surface of the glass slide, creating a 'smear' for analysis. The sample must then be allowed to dry. Subsequently, the dried smear needs to be heat fixed by carefully passing the slide through the flame of a Bunsen burner. This step helps the cells adhere to the slide and prepares them for subsequent staining and analysis. Finally, the used swab must be disposed of in biohazard waste to maintain safety protocols.
For the result of a DNA test to confirm a child's relationship to their supposed parents, the child's DNA fingerprint must show significant genetic overlap with the DNA of both parents. This genetic overlap is due to the child inheriting half of their DNA from each biological parent. These similarities are what can establish that the child is related to the mother and father.