Methods are provided for determining the identity of a polymorphic nucleotide in a complex mixture of nucleic acids where one or more distinct polymorphisms can be present in the mixture, and multiple polymorphisms can be screened in parallel. Target nucleic acids are amplified using bridge amplification techniques. The detection and identification of the specific polymorphic residue(s) is based on readout methods that utilize the specificity of specific enzymes for complementary DNA sequences. These approaches result in a labeled nucleotide covalently attached to the amplicon, where the identity of the nucleotide is informative of the polymorphic sequence. In one aspect, the readout process uses primer extension protocols, where the specific base incorporated by DNA polymerase is determined by the sequence at the polymorphic site. In another aspect, the identity of a specific base hybridized and ligated to the amplicon is determined by the sequence at the polymorphic site. The polynucleotide to which the label has been attached can be detected in situ, i.e. bound to the solid substrate used for amplification; or can be released and detected.
本发明提供了确定复杂核酸混合物中多态核苷酸特性的方法,混合物中可能存在一种或多种不同的多态性,可同时筛选多种多态性。使用桥式扩增技术扩增目标核酸。利用特异性酶对互补 DNA 序列的特异性,通过读出方法来检测和识别特定的多态残基。这些方法可将标记的核苷酸共价连接到扩增子上,核苷酸的特性可提供多态序列的信息。一方面,读出过程使用引物延伸协议,
DNA 聚合酶结合的特定碱基由多态位点的序列决定。另一方面,与扩增子杂交和连接的特异碱基的身份由多态位点的序列决定。附有标签的多核苷酸可在原位检测,即与用于扩增的固体底物结合;也可释放后检测。