How do scientists get DNA from a strand of hair?

Answer 1

Forensic investigators look for two different types of DNA in a strand of hair. Traditionally they look for nuclear DNA (nDNA) which comes from the nucleolus and you can get that if the strand of hair as the follicle intact and not too damaged. This is primary, but you can still get DNA from the hair shaft itself without the use of the follicle. This is Mitochondrial DNA (mtDNA), and though this type of DNA has less information than nuclear DNA, it is very stable and that's great for investigators or scientists because you can even extract that type of DNA from mummies that are many thousands of years old. So if you're wondering if you can be caught by the police if all they have is a piece of hair with no follicle, yes you can! The downside of using mtDNA versus nDNA is mitochondrial DNA is passed on from the mother, so if you pluck 3 pieces of hair, one from the mother, one from the brother, and the other from the sister, they will ALL be identical. So in this case it is no good at determining who is who. But if it's a random murder site where the suspect is being matched with a hair shaft, they are able to make a positive ID match that hair.

Answer 2

Scientists can extract DNA from a strand of hair by first breaking down the cell membrane to release the DNA. This is typically done through a process called cell lysis. Once the DNA is released, it can be purified and extracted using techniques like polymerase chain reaction (PCR) for further analysis.

Answer 3

To extract DNA from a strand of hair, scientists typically follow these steps: First, the hair sample is washed to remove any external contaminants. Next, the hair is cut into small pieces and placed in a solution that breaks down the hair's proteins. Enzymes are then used to break down the cell membrane and release the DNA. Finally, the DNA is purified using various techniques such as centrifugation or filtration.