The Establishment of a Sheep Embryo Genomic Selection System

Area of Science:

• Animal Genetics
• Reproductive Biotechnology
• Genomic Selection

Background:

• Conventional genomic selection (GS) is time-consuming and uncertain.
• Embryo genomic selection (EGS) integrates GS with embryo biotechnology for enhanced breeding efficiency.
• Pre-implantation genomic prediction can significantly reduce breeding cycle duration.

Purpose of the Study:

• To establish a reliable embryo biopsy-based GS pipeline for sheep.
• To optimize whole-genome amplification and genotyping techniques for minute embryonic samples.
• To validate the accuracy of EGS for predicting breeding values in sheep.

Main Methods:

• Development of an in vitro sheep embryo production platform compatible with biopsy.
• Comparison of Multiple Displacement Amplification (MDA) and MALBAC for whole-genome amplification.
• Genotyping of low-cell-number embryo samples and imputation using whole-genome sequencing data.

Main Results:

• High-quality genotypes were obtained from embryos with as few as 10 cells using optimized WGA methods.
• Imputation significantly improved genotype call rates and accuracy.
• High concordance between embryo and lamb genotypes and strong correlations (R²: 0.91-0.98) for genomic estimated breeding values (GEBVs) were observed.

Conclusions:

• The developed EGS pipeline enables accurate pre-implantation genomic evaluation in sheep.
• This strategy significantly accelerates genetic improvement in sheep breeding programs.
• EGS offers a powerful tool to enhance breeding efficiency and reduce uncertainty in sheep.