Dr. Donagh Berry, Teagasc answered the question “How can twins have completely different genetics?” at the ICBF & Sheep Ireland Genetics Conference which took place Friday 17th of January 2020 in the Heritage Hotel, Killenard, Co. Laois with a very interesting pretension on breeding and genomics.
The presentation can be found here
Some of Donaghs’ take home messages include:
- There can be a significant difference in the performance in a set of twins, as each set is unlikely to get the exact same genes from each parent
- Lambs from the same litter having multiple sires is common place in flocks that mob mate. Some flocks have been found to be as high as 33% of litters having multiple sires
- Genomics allows us to better define the relationships between animals, allow us to better understand how that animal will perform based on its ancestors performance
Genomics is all about gaining a better understanding of an animals relationship to the animals in the wider genotyped population. Currently we assume that every time a lamb is born a ram passes on the same half of his DNA each time but we know this is not the case. Until now this was the best method we had for defining what was going to be passed to the next generation until we started to receive performance records from that animal as well. Now with genomics, we can much more accurately decipher which genes the lambs got from the sire and dam, and then based on this give a better prediction of how that animal will perform over its live time.
Genomics is also opening the door for some commercial flocks to start using genomics to assign parentage, allowing them to mob mate instead of single sire mating. Eamon wall cover this in more detail in his presentation which can be found here.