the present invention discloses a method that can be used to identify one dna sequence or one specific group of dna sequences from a complex biological sample . diverse molecular biology methods require the use of short dna sequences , called oligonucleotides , that are artificially synthesized from a description of their composing bases . the disclosed method allows the design of oligonucleotides useful for said molecular biology procedures , like probe design procedures , and is characterized by the construction of a database of reference sequences , the selection of a subset of sequences belonging to target organisms , the selection of candidate oligonucleotides from such sequences , the depuration of these candidate oligonucleotides according to hybridization specificity and thermodynamic stability criteria , and the sorting of such oligonucleotides according to their taxonomic specificity . in a second aspect , a method is disclosed to design oligonucleotides pairs or primers , which are required in certain molecular biology techniques , like polymerase chain reaction techniques . this method is similar to the first aspect of the invention , but thermodynamically compatible oligonucleotides pairs or primers that hybridize to the same sequence at a distance which is within a given range are evaluated .