Production of transgenic sheep

Area of Science:

• Animal biotechnology
• Genetics and genomics
• Agricultural science

Background:

• Transgenic sheep production faces significant challenges compared to other species, with lower success rates and higher workloads.
• Despite difficulties, the potential benefits for human/animal health and agriculture drive continued research.
• Low transgenesis efficiency (approx. 1%) limits critical investigations into transgene expression, phenotypic effects, and construct optimization.

Purpose of the Study:

• To highlight the difficulties and inefficiencies in transgenic sheep production.
• To emphasize the importance of improving transgenesis rates for agricultural and health applications.
• To establish pronuclear microinjection as the current benchmark method for sheep transgenesis.

Main Methods:

• Review of existing literature on transgenic sheep production.
• Analysis of the efficiency of pronuclear microinjection in sheep embryos.
• Comparison of gene expression and phenotypic effects in sheep versus mouse models.

Main Results:

• Transgenic sheep production success rates are approximately 1% of injected embryos.
• The mouse model may not accurately predict transgene behavior in sheep, as demonstrated by the GH9 gene.
• Pronuclear microinjection is the established method for regular production of transgenic sheep.

Conclusions:

• Improving transgenesis efficiency in sheep is crucial for advancing agricultural and biomedical applications.
• Current methods, particularly pronuclear microinjection, are inefficient but serve as the standard for evaluating new techniques.
• Further research is needed to overcome the limitations in sheep transgenesis and fully realize its potential benefits.