Patent ID: 6856915

Claim:
A method for determining the similarity at the genome level between a target organism and a reference organism comprising the steps of: a) preparing one or more of double-stranded DNA fragments by random PCR using, as a template, genome DNA of the target organism, b) subjecting said double-stranded DNA fragments prepared in step a) to temperature gradient gel electrophoresis (TGGE) or denaturant gradient gel electrophoresis (DGGE), wherein an internal reference double-stranded DNA prepared in advance, is co-migrated with the double-stranded DNA fragments, c) assigning each melting initiation point and/or each mobility transition end point of the double-stranded DNA fragments prepared in step a) and both the melting initiation point and the mobility transition end point of the internal reference double-stranded DNA co-migrated from an electrophoretic pattern obtained in step b), d) normalizing each coordinate of melting initiation point and/or mobility transition end point of the double-stranded DNA fragments using those of the melting initiation point and mobility transition end point of the internal reference double-stranded DNA to eliminate experimental fluctuations and generate species identification dots, e) calculating PaSS (Pattern Similarity Score) defined by equation 1 below: PaSS=1−{Σγ( i )}/ n (1) where ‘Σ’ denotes the summation over i=1 to n (where n is the number of the species identification dots used for the calculation), and γ(i) is expressed by equation 2 below: γ( i )=2 ×|V 1i −V 0i |/(| V 1i |+|V 0i |) (2) where V 0i represents position vector of the i-th species identification dots of the reference organism and V 1i represents position vector of the i-th species identification dots of the target organism; using species identification dots obtained in step d) and species identification dots of the reference organism to determine the similarity at the genome level between the target organism and the reference organism, wherein the species identification dots of the reference organism is separately obtained by a method in which steps a) to d) are carried out under the same conditions.