High-Speed Mouse Backcrossing Through the Female Germ Line

Area of Science:

• Genetics
• Animal Models
• Genomic Engineering

Background:

• Congenic mouse strains are vital for analyzing gene function and quantitative trait loci.
• Traditional speed congenic breeding is time-consuming, often exceeding one year.
• Existing methods require males to reach sexual maturity before the next generation.

Purpose of the Study:

• To develop a faster method for producing congenic mouse strains.
• To reduce the time and cost associated with congenic strain generation.
• To demonstrate the feasibility of superovulation-aided backcrossing in mice.

Main Methods:

• Utilized marker-assisted selection for speed congenic breeding.
• Implemented superovulation in marker-selected females to induce early ovulation.
• Performed backcrossing through the female germline to accelerate generational transfer.

Main Results:

• Successfully transferred a transgenic strain to a >99% C57BL/6J background in 10 months.
• Reduced generation time to approximately 7 weeks per generation.
• Achieved efficient congenic strain production with fewer than 60 mice total.

Conclusions:

• Superovulation-aided backcrossing through the female germline is a practical and efficient method.
• This technique significantly accelerates the generation of congenic mouse strains.
• The approach is effective with minimal animal numbers, reducing research costs.