DNA samples are collected through various methods, primarily by obtaining biological material that contains cells with DNA. This often involves non-invasive techniques, but can also include more direct sampling depending on the context (e.g., forensic investigation).
Common Methods of DNA Sample Collection
- Swabbing: This is a common technique used to collect DNA from surfaces.
- Buccal Swab: Swabbing the inside of the cheek (buccal cells) is a standard method for collecting DNA for identification purposes.
- Surface Swabbing: Swabbing biological stains like blood or semen, or items touched by a potential suspect, gathers DNA evidence.
- Scraping: Scraping fingernails can retrieve DNA from under the nails, potentially linking individuals to a crime or event.
- Collection of Objects: Items suspected of being touched by an individual (e.g., a weapon, a glass) are collected as evidence, with DNA extracted from any cells left behind.
- Liquid Samples: Blood or saliva samples can be directly collected and processed to extract DNA.
- Specialized Vacuuming: In forensic settings, investigators may use a specialized vacuum cleaner, called an MVAC, to collect trace amounts of DNA from clothing, furniture, or other surfaces.
Examples in Practice
- Forensic Science: Collecting blood stains from a crime scene. Scraping under the victim's fingernails. Gathering a weapon for potential DNA evidence.
- Paternity Testing: Collecting a buccal swab from the alleged father and the child.
- Medical Diagnostics: Collecting a blood sample for genetic testing.
- Ancestry Testing: Collecting a saliva sample.
In all cases, proper handling and storage of the collected material are crucial to prevent contamination and ensure accurate DNA analysis.
