Abstract: The invention provides for a method of producing a mutant somatic human cell line of cells comprising a genomic mutation of interest (MOI) at a predefined genomic site of interest (GOI) in close proximity to a genomic target site, which comprises: a) providing a guide RNA (gRNA) comprising a tracrRNA in conjunction with crRNA including an oligonucleotide sequence that hybridizes with the target site; b) providing an RNA-guided endonuclease which catalyzes the DNA break at the target site upon hybridizing with the gRNA; c) introducing the gRNA into the cells in the presence of the endonuclease to obtain a repertoire of cells comprising a variety of genomic mutations at the target site; d) selecting a cell from said repertoire which comprises a MOI; wherein the cell is haploid for the genomic locus of the target site; and e) expanding the cell to obtain the mutant cell line.

Abstract: The invention provides for a somatic fully haploid, karyotypically stable human cell line, e.g. obtainable by targeted deletion of one or more disomic chromosomal regions of a somatic near-haploid human parental cell, a method of producing the same, as well as the use of the cell line for producing isogenic cell variants, comprising genomic mutations at different genomic target sites, and a library of such cell variants.

Abstract: The invention provides for a somatic fully haploid, karyotypically stable human cell line, e.g. obtainable by targeted deletion of one or more disomic chromosomal regions of a somatic near-haploid human parental cell, a method of producing the same, as well as the use of the cell line for producing isogenic cell variants, comprising genomic mutations at different genomic target sites, and a library of such cell variants.