Abstract: A method of preparing DNA fragments, which entails at least the following steps of: a) preparing double-stranded DNA fragments from a sample of nucleic acids to be analyzed, b) ligating the ends of said DNA fragments to a double-stranded oligonucleotide adaptor (adaptor AA?) comprising the recognition site for a restriction enzyme, the cleavage site of which is located downstream of said recognition site, c) amplifying the fragments linked to said adaptor, using a pair of suitable primers, at least one being optionally labeled at its 5? end, and d) cleaving said DNA fragments close to one of their ends, using said restriction enzyme, so as to generate short fragments.

Abstract: The invention relates to a method of preparing DNA fragments by selective fragmentation of nucleic acid fragments. The inventive method comprises a first selection step involving selection of short fragments, consisting in: a) preparing first double-stranded DNA fragments F1 using at least one restriction enzyme E1 which can randomly fragment the nucleic acid sample to be analysed, by generating said DNA fragments F1 with blunt or cohesive ends; b) ligating the ends of the DNA fragments F1 obtained in step (a) to at least one adapter AA?; c) cleaving the DNA fragments F1 obtained in step (b) using a restriction enzyme E2, such as to select a fraction of short fragments F2; and d) using any suitable means to purify the aforementioned fraction of short fragments F2.

Abstract: The invention relates to a method of preparing DNA fragments and to the applications thereof, in particular for the hybridisation of nucleic acids. The inventive method is essentially characterised in that it consists of at least the following steps comprising: (a) preparation of double-stranded DNA fragments from a sample of nucleic acids to be analysed; (b) ligation of the ends of the aforementioned DNA fragments to a double-stranded oligonucleotide adapter (adapter AA?) comprising the site for the recognition of a restriction enzyme of which the cleavage site is situated downstream of said recognition site; (c) amplification of the fragments linked to the above-mentioned adapter, using a pair of suitable primers, one of which is optionally marked at the 5? end thereof; and (d) cleavage of said DNA fragments close to one of the ends of same, using the restriction enzyme, such as to generate short fragments.