How to create a live mouse? - briefly
Produce a living rodent by mating genetically suitable adults, confirming successful conception, and providing appropriate gestational and post‑natal care until the offspring reach maturity.
How to create a live mouse? - in detail
Producing a viable laboratory mouse involves precise coordination of genetics, embryology, and animal husbandry. The process begins with selection of a suitable genetic background, proceeds through manipulation of fertilized embryos, and ends with post‑natal monitoring.
The initial step is strain selection. Researchers choose an inbred line that matches experimental goals, ensuring reproducibility and minimizing genetic variability. Once the strain is defined, breeding pairs are set up to generate oocytes and sperm under controlled conditions.
Embryo manipulation follows a defined sequence:
- Harvest fertilized zygotes from super‑ovulated females within 0.5–1.5 hours post‑coitum.
- Perform the desired genetic alteration, such as CRISPR‑Cas9 editing, pronuclear injection, or embryonic stem cell integration.
- Culture embryos in a defined medium at 37 °C, 5 % CO₂, monitoring development to the blastocyst stage (approximately 3.5 days).
- Transfer viable blastocysts into the uterine horns of pseudopregnant recipient females, typically 2–3 embryos per horn.
Gestation proceeds under standard laboratory conditions: temperature‑controlled housing, ad libitum access to feed and water, and minimal stress exposure. Parturition occurs around day 19–20, after which newborns are inspected for viability, weight, and any phenotypic markers introduced by the genetic manipulation.
Post‑natal care includes:
- Identification and tagging within 24 hours.
- Monitoring growth curves and health status weekly.
- Conducting genotyping assays (PCR, sequencing) to confirm the presence of the intended modification.
- Providing enrichment items to promote normal behavior and reduce stress.
Throughout the workflow, strict adherence to ethical guidelines and institutional animal care protocols is mandatory. Documentation of each stage—strain provenance, embryo manipulation details, implantation records, and health assessments—ensures traceability and compliance with regulatory standards.