Ligation free methods of nucleic acid library preparation

A method of preparing a library of nucleic acids, comprising:

• a. providing a sample of nucleic acids comprising at least one sequence of interest;
• b. blocking 3′ ends of the nucleic acids, thereby preventing polymerase extension of the 3′ ends;
• c. contacting the sample of nucleic acids with a plurality of first polymerase chain reaction (PCR) primers, and a first polymerase under conditions that allow PCR to occur, thereby generating a plurality of first single-sided PCR products;
• d. contacting the plurality of first single-sided PCR products with a terminal transferase and dNTPs under conditions sufficient to transfer dNTPs to 3′ ends of the plurality of first single-sided PCR products, thereby generating a plurality of PCR products comprising 3′ tails;
• and
• e. contacting the plurality of PCR products comprising 3′ tails with a plurality of second PCR primers and the first polymerase under conditions that allow PCR to occur;
• thereby generating a library of nucleic acids with adapters at 5′ and 3′ ends.