Final answer:
The first step in isolating DNA is cell lysis, which involves breaking open cells to extract DNA. Polymerase Chain Reaction (PCR) is used later for amplifying specific DNA sequences after the DNA has been isolated.
Step-by-step explanation:
The first step in isolating DNA is cell lysis. This involves breaking open the cellular structures to release the DNA within. Once the cells are lysed using a detergent solution that disrupts the cell membranes, the DNA can be separated from other cellular components. After cell lysis, enzymes are often used to remove undesired macromolecules such as proteins and RNA, and the DNA is subsequently precipitated out of solution using alcohol.
Polymerase Chain Reaction (PCR), while incredibly important for amplifying specific regions of DNA, is not the initial step in DNA isolation. PCR is used after DNA has been isolated to rapidly increase the number of copies of specific DNA sequences, facilitating various analyses including genetic testing, forensic investigation, and research studies.