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Updated: Jun 24, 2026
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Mouse Round Spermatid Injection
Published on: January 26, 2024
A high-speed congenic strategy using first-wave male germ cells
Narumi Ogonuki1, Kimiko Inoue, Michiko Hirose
1RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
Plos One
|April 1, 2009
Summary
This study introduces a rapid congenic breeding system for mice, significantly reducing the time to develop genetically uniform strains. This new method accelerates the analysis of gene functions on specific genetic backgrounds.
Area of Science:
- Genetics
- Animal Models
- Molecular Biology
Background:
- Congenic breeding is crucial for genetic research in mice and rats.
- Traditional methods are time-consuming, taking 3-4 years for high genetic purity.
- Existing speed congenic strategies still require over a year.
Purpose of the Study:
- To develop a significantly faster method for creating congenic mouse strains.
- To reduce the time required for genetic background analysis.
- To accelerate the study of gene function and quantitative trait loci.
Main Methods:
- Utilized round spermatids from immature donor mice (22-25 days old).
- Employed a speed congenic strategy with marker-assisted selection.
- Injected donor round spermatids into recipient oocytes for rapid backcrossing (N4-N5).
Main Results:
- Established three congenic strains (transgenic, knockin, ENU-mutant) in approximately half a year.
- Achieved high recipient genome purity (up to 100% homozygous at N5).
- Demonstrated fertility of carrier males for gene propagation.
Conclusions:
- The new high-speed breeding strategy drastically shortens congenic strain production time.
- Enables rapid definition of gene effects on desired genetic backgrounds.
- Offers the fastest protocol for precise genetic analysis.
