METHODS AND COMPOSITIONS FOR TARGETED GENETIC MODIFICATION USING PAIRED GUIDE RNAS Russian patent published in 2020 - IPC C12N15/90 C12Q1/68 C12N9/22 A61K48/00 

FIELD: genetic engineering.

SUBSTANCE: disclosed is a method of introducing a biallelic modification into a target genomic locus using a CRISPR/Cas9 system, comprising administering Cas9, two guide RNAs and a targeting vector, containing a polynucleotide insert flanked by 5' homologous arm which hybridizes with target 5'-sequence within the target genomic locus, and 3' homologous arm, which hybridizes with target 3'-sequence within the target genomic locus. Present method also includes conducting a quantitative test for assessing the modification of the allele and the preservation test to determine the number of copies in the genomic DNA sample of the region of target 5'- and/or 3'-sequence, which enables distinguishing a correct targeted insert of a polynucleotide insert from random transgenic inserts and/or correct directed deletions from deletions that go beyond the region of the target genomic locus.

EFFECT: methods and compositions for targeted genetic modification using paired guide RNA.

32 cl, 18 dwg, 14 tbl, 7 ex