Evidence map›Paper›PMID 42754893›Full record

ArticleGenome medicine2026

Accurate characterization of CRISPR-Cas9 genome editing outcomes and mosaicism with near-perfect long reads.

Ida Höijer, Robin van Schendel, Anastasia Emmanouilidou, Rebecka Östlund, Ignas Bunikis, Marcel Tijsterman, Marcel den Hoed, Adam Ameur

Abstract read
In one paragraph

Article in Genome medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Ida HöijerDepartment of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden. ida.hoijer@igp.uu.se.ORCID http://orcid.org/0000-0002-3915-3384
Robin van SchendelDepartment of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
Anastasia EmmanouilidouDepartment of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Rebecka ÖstlundDepartment of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Ignas BunikisDepartment of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Marcel TijstermanDepartment of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
Marcel den HoedDepartment of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Adam AmeurDepartment of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden. adam.ameur@igp.uu.se.ORCID https://orcid.org/0000-0001-6085-6749

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundGenetic mosaicism is a well-recognized consequence of CRISPR-Cas9 genome editing, yet its characterization remains challenging, especially when it involves low-frequency structural variants. A comprehensive analysis of mosaicism requires deep and unbiased sequencing of the target loci, with accurate single-molecule reads.

methodsWe performed amplification-free PureTarget PacBio sequencing to investigate CRISPR-Cas9 outcomes at on-target and off-target sites in genome edited zebrafish and their offspring. CRISPR-Cas9 genome editing was performed by micro-injection in fertilized eggs at the single-cell stage.

resultsThirty samples from pooled larvae and individual zebrafish were successfully sequenced, resulting in > 1100x average target coverage. The PacBio reads reached an exceptional accuracy (QV39) over the target regions, with every read originating from a unique DNA molecule. The two haplotypes of the target loci displayed a balanced depth of coverage, while long-range PCR of the same samples resulted in skewed data. Further analysis of the PureTarget data revealed widespread genetic mosaicism in individual founder (F0) fish, with up to 18 distinct on-target events and 11 off-target events present in a single adult founder. Several CRISPR-Cas9 editing outcomes, including large structural variants and off-target mutations, were inherited to the F1 generation. Notably, as many as seven unique editing events were found among sibling F1 juvenile offspring derived from a single founder pair, thereby confirming the presence of genetic mosaicism in germ cells of founder zebrafish. This implies that some consequences of CRISPR-Cas9 editing may emerge only in the second generation. We also analyzed DNA methylation signals in the PureTarget data but did not observe altered 5mC CpG levels in genome edited samples.

conclusionsPureTarget enables efficient, accurate, and unbiased profiling of genetic mosaicism and DNA methylation at pre-defined genomic regions. Our results show that CRISPR-Cas9-induced mosaicism is widespread and represents an important factor to consider in genome editing experiments.

Indexed as

CRISPR-Cas SystemsGene EditingMosaicismAnimalsGenomeHigh-Throughput Nucleotide SequencingZebrafishCRISPR-Cas9Genome editingLong-read sequencingMosaicismOff-target mutationsPureTargetSingle-molecule sequencingStructural variationTargeted sequencing

Identifiers

PMID42754893
PMCPMC13587479

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.