In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
Q: DNA paternity testing is the use of DNA profiling (known as genetic fingerprinting) to determine whether two individuals are biologically parent and child. A paternity test establishes genetic proof whether a man is the biological father of an individual, and a maternity test establishes whether a woman is the biological mother of an individual. Tests can also determine the likelihood of someone being a biological grandparent to a grandchild. Though genetic testing is the most reliable standard, older methods also exist, including ABO blood group typing, analysis of various other proteins and enzymes, or using human leukocyte antigen antigens. The current techniques for paternity testing are using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Paternity testing can now also be performed while the woman is still pregnant from a blood draw.
A:
what is the basic principle of a dna test