Haploid Genetic Screening - Genetic Screens


Definition: Relating to a cell or nucleus; having a single set of unpaired chromosomes

Haploid human cells are perfectly suited for genetic studies. Unlike most commonly used cell lines which possess at least two (and sometimes many more) copies of each gene, haploid cells have only one, and thus require the inactivation of a single allele to elucidate its loss-of-function phenotype. The obtained results are precise, robust and translate well into other model systems.

Haploid Screening Platform

Leverage Horizon’s haploid genetic screening platform to:

  • Identify novel drug targets
  • Profile drugs to identify mechanisms of resistance
  • Stratify patient populations in clinical trials
  • Identify downstream effectors
  • Derive testable hypotheses for the mechanism of action

Benefits of Haploid Cells

  • Cell line of human origin
  • Every gene present in a single copy
  • Amenable to genetic manipulation
  • Phenotype of single mutation immediately apparent
  • Great knowledgebase available (WGS, RNA sequencing, essentiality dataset)

Request more information

Haploid and Near-haploid Cells

The following cell types are available for screens:

KBM-7 Cells


  • Near-haploid (diploid chr8, chr15)
  • Isolated from CML patient
  • Myeloid lineage
  • Suspension cells
HAP1 Cells


  • Near-haploid (chr15)
  • Derived from KBM-7
  • Fibroblast like
  • Adherent cells
eHAP Cells


  • eHAP
  • Fully haploid
  • Derived from HAP1
  • Patent EP 13194940.6

Haploid genetic screening platform

Haploid Genetic Screens

To manage the risk of the screening project, evaluation of project feasibility will take place after each phase and termination of the project is possible if there is no chance to succeed.

How do haploid genetic screens work?

  1. Haploid cells are mutagenized using retroviral gene trapping. This generates a population of cells in which every cell lines carries at least one gene trap insertion, thus resembling a gene knockout.
  2. Mutant pools are treated with a drug or drug candidate that affects cell viability or cell proliferation.
  3. The vast majority of mutants die, but a few drug resistant clones survive and expand.
  4. Location of gene trap insertions is determined by amplifying adjacent sequences by PCR, followed by next generation sequencing.

Life/death viability screens can be completed within 14-18 weeks.

Retroviral Gene Trapping

Gene Trap

In retroviral gene trapping, a DNA sequence is inserted randomly throughout the genome of cells.  When this insertion occurs in an intron of a gene, it prevents proper exon-exon splicing, and introduces a polyadenylation signal so that transcription of the cognate gene is terminated.

Resistance Screening


ABT-737 Screen in KBM-7 Cells Mutagenized with Gene Trapping


The screen resulted in two significant hits:

  • BAX: 51 independent insertions (p-value 10-111)
  • NOXA: 39 independent insertions (p-value 10-70)

Genetic inactivation of pro-apototic BAX or NOXA prevents induction of apoptosis by ABT-737 and makes cells resistant to the drug.

Thus, results suggest important determinants for ABT-737 sensitivity and provide insights into the mechanism of action of the drug.

Why use haploid genetic screens?

Haploid Genetic Screen Benefits Table

Learn more about our Haploid genetic screening services in our archived webcast

Back to top