The Role of Genomics in Assessing Embryo Transfer Lambs

Embryo transfer is a powerful reproductive technology for increasing the number of lambs born with the same parents and having similar genetic makeup. However full siblings aren’t genetically identical, while they get half of their genes from each parent they don’t inherit the same genes as one another.

When trying to assess the breeding merit of an unrecorded sheep in a pre-genomic era we would know that siblings obtained 50% of their genes from each parent and on that basis lambs would automatically get a breeding value based on “mid-parent average” i.e. half-way between either parent. Now the genomic data is used within Signet’s genetic analyses, we can start to identify exactly which genes are passed on to the progeny from a specific mating and the breeding values produced will reflect this.

In this real-life example, a Charollais ewe yielded a number of embryos and whilst none of the lambs were weight recorded; the use of genomic information from Charollais lambs that had been weight recorded identified important differences between them.

In the graph below we can see that even with a relatively small increase in accuracy we can identify a lamb that is genetically superior to either parent and one that is 26 index points lower than would initially be predicted from this mating.

A difference of more than 50 index points between full ET offspring, highlights the potential in using genomic information to identify elite breeding stock within a Charollais population that often contains sheep with quite similar genetics.

 

Samuel Boon and Laura Eyles, Signet Breeding Services