Patent ID: 6777188
Filing Date: 2004-08-17
Classification: C07H,C12N,C12P,C12Q

Abstract:
A method for genotyping a diploid organism, comprising:providing two alleles of a target gene of a diploid organism suspected to contain a polymorphism; obtaining a first segment of one allele wherein the segment contains the suspected polymorphic locus; obtaining a second segment from the other allele wherein the segment also contains the suspected polymorphic locus; replacing a natural nucleotide at greater than 90% of its points of occurrence in the first and the second segment with a modified nucleotide to give a first and a second modified segment; wherein, the natural nucleotide that is replaced is not a nucleotide involved in the polymorphism; replacing the natural nucleotide with a modified nucleotide comprises amplification using a primer that hybridizes to each segment such that, after amplification, a first modified nucleotide is incorporated between the 3â€² end of the primer and the polymorphic locus; and, a second modified nucleotide is located from 5 to 20 nucleotides downstream of the first modified nucleotide; cleaving the first and second modified segments at greater than 90% of the points of occurrence of the modified nucleotide to give a first and second set of fragments each of which comprises a 5-20 nucleotide fragment; and, comparing masses of the 5-20 nucleotide fragments obtained from the first and the second modified segment to detect the presence or absence of the polymorphism.