Method of double stranded DNA synthesis

A method for synthesizing a double stranded DNA having a predetermined orientation, wherein a first strand of the double-stranded DNA is complementary to a selected RNA or DNA template, comprising:

• synthesizing the first strand by contacting the selected RNA or DNA template with:
• (a) a polynucleotide linker/primer comprising a first restriction site and being sufficiently complementary to the template to hybridize therewith;
• (b) a suitable RNA or DNA dependent DNA polymerase;
• and
• (c) a deoxyribonucleotide triphosphate analog, under conditions effective to permit the polymerization of the first strand,
• wherein the linker/primer and the deoxyribonucleotide triphosphate analog are selected such that the linker/primer is capable of being cleaved at the first restriction site and incorporation of the deoxyribonucleotide triphosphate analog in the first strand protects the double stranded DNA from cleavage under conditions sufficient to cleave or substantially cleave the linker/primer at the first restriction site,
• synthesizing a second strand complementary to the first strand, thereby producing a double stranded DNA, and
• ligating restriction site adaptors to the double stranded DNA, wherein the adaptors comprise a second restriction site that is different from the first restriction site.