Which of the following is NOT an advantage of DNA testing?

DNA testing is a powerful tool in forensic science, and understanding its advantages is crucial for effective application. The assertion that DNA cannot be analyzed from hair is accurate because hair typically does not contain a nucleus unless there are follicles attached, which are rare in forensic samples. Hence, the ability to extract usable DNA from hair samples without the root means it is not a reliable source for DNA testing in many cases.

In contrast, the other options highlight significant advantages of DNA testing. DNA is present in all nucleated cells, making it accessible from a variety of biological samples including blood, saliva, and tissues. Its uniqueness to each individual contributes to its effectiveness in personal identification and exclusion in criminal investigations, providing a high level of certainty regarding the identity of individuals. Additionally, DNA remains relatively stable over time, allowing for analysis even after long periods, which is essential for cold cases or instances where immediate testing is not possible.

Understanding these characteristics of DNA testing emphasizes its strengths and its capabilities in forensic contexts, making it a cornerstone of modern investigative processes.