Evidence map›Paper›PMID 17331107›Full record

ArticleGenes, brain, and behavior2007

Interpretation of knockout experiments: the congenic footprint.

L C Schalkwyk, C Fernandes, M W Nash, K Kurrikoff, E Vasar, S Kõks

Abstract read
In one paragraph

Article in Genes, brain, and behavior, 2007. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 30 papers.

0numbers the graph read from it
0cells of the map it votes in
30citing 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

30 citing papers in PubMed.

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  10. At the dawn of the transcriptomic medicine.Experimental biology and medicine (Maywood, N.J.) · 2021
    Review
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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

6 authors.

L C SchalkwykSocial, Genetic and Developmental Psychiatry Centre (PO82), Institute of Psychiatry, King's College London, London, United Kingdom. l.schalkwyk@iop.kcl.ac.uk
C Fernandes
M W Nash
K Kurrikoff
E Vasar
S Kõks

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

In gene targeting experiments, the importance of genetic background is now widely appreciated, and knockout alleles are routinely backcrossed onto a standard inbred background. This produces a congenic strain with a substantial segment of embryonic stem (ES)-cell-derived chromosome still flanking the knockout allele, a phenomenon often neglected in knockout studies. In cholecystokynin 2 (Cckbr) knockout mice backcrossed with C57BL/6, we have found a clear 'congenic footprint' of expression differences in at least 10 genes across 40 Mb sequence flanking the Cckbr locus, each of which is potentially responsible for aspects of the 'knockout' phenotype. The expression differences are overwhelmingly in the knockout-low direction, which may point to a general phenomenon of background dependence. This finding emphasizes the need for caution in using gene knockouts to attribute phenotypic effects to genes. This is especially the case when the gene is of unknown function or the phenotype is unexpected, and is a particular concern for large-scale knockout and phenotypic screening programmes. However, the impact of genetic background should not be simply viewed as a potential confound, but as a unique opportunity to study the broader responses of a system to a specific (genetic) perturbation.

Indexed as

AnimalsBehavior, AnimalChromosome MappingDNA, IntergenicGenomeMiceMice, CongenicMice, Inbred C57BLMice, KnockoutReceptor, Cholecystokinin BDNA, IntergenicReceptor, Cholecystokinin B

Identifiers

PMID17331107
PMCPMC1890814

What OpenQuestion holds

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Registered trials

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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.