One-Step Homology Mediated CRISPR-Cas Editing in Zygotes for Generating Genome Edited Cattle

Area of Science:

• Animal Genetics
• Molecular Biology
• Biotechnology

Background:

• Traditional selective breeding is insufficient for rapid adaptation in livestock.
• Global challenges like climate change and pandemics necessitate faster genetic improvement in cattle.
• Long cattle generation intervals hinder traditional breeding strategies for critical trait introgression.

Purpose of the Study:

• To demonstrate the efficacy of CRISPR-Cas genome editing for introducing PRNP allelic variants in cattle.
• To establish a framework for rapid genetic improvement in livestock using genome editing.
• To develop cattle with enhanced resilience to prion diseases.

Main Methods:

• CRISPR-Cas genome editing was employed for targeted modification of PRNP alleles in cattle zygotes.
• Embryo injections were performed, followed by pregnancy establishment and offspring analysis.
• Unbiased deep-sequencing was utilized to assess editing outcomes and homology-directed repair efficiency.

Main Results:

• Seven genome-edited cattle offspring were born from six pregnancies.
• Two founder animals exhibited over 90% targeted homology-directed repair modifications.
• A methodology for in vitro optimization and efficient generation of edited calves was established.

Conclusions:

• CRISPR-Cas genome editing enables rapid and precise introgression of beneficial alleles in cattle.
• This approach provides a viable strategy for enhancing livestock resilience to diseases, including prion pandemics.
• The study establishes a foundation for future applications of genome editing in animal agriculture to address global food security and health challenges.