A "bit of hair nyt" is a minute hair fragment utilized in genetic testing. This can be used to identify an individual through DNA analysis, as each person's genetic code is unique.
Hair samples are a valuable source of DNA for genetic testing because they are easily collected and can be stored for long periods of time. They are also relatively non-invasive to collect, making them a good option for people who are uncomfortable with giving blood or saliva samples. Historically, the development of DNA fingerprinting in the 1980s revolutionized the use of hair samples for identification purposes.