Title: Breeding Danish Shorthorn in the future – Genomic mapping of shorthorn populations
Project description
At Center for Quantitative Genetics and Genomics (QGG), Aarhus University, we work with genomic characterisation and improvement of sustainable preservation of live livestock genetic resources. Within the past five years we have mapped the genetic diversity and relationship of 12 old, Danish livestock breeds, among others three of the four old cattle breeds worthy of preservation: The Danish red dairy breed anno 1970 (RDM-70), the black Danish dairy breed anno 1965 (SDM-65) and the Danish Shorthorn. These studies determined that Danish Shorthorn have an average degree of genomic inbreed of 33% (Szekeres et al. 2016), which is very high and alarming. It reflects a very small population with a low genetic variation. In the future, the degree of genomic inbreed will grow concurrently with the continuous growth of the degree of relationship in a small population. An additional increase of the degree of inbreed will result in a weakened reproduction ability, reduced life force, and a reduced resistance to diseases and subsequently an impaired health. Signs of reduced reproduction ability in Danish Shorthorn are found, but at present, it cannot be established if this is caused by depression of inbreeding.
A sustainable preservation programme for Danish Shorthorn is therefore indispensable to secure the survival of the race. A continuous loss of genetic variation will lead to inbreed depression – even within a relatively short time. Establishing a sustainable preservation programme requires a sufficient amount of animals with a sufficient genetic variation, a knowledge of the relationship between the animals in the breed, and an insurance that the existing, genetic variation is preserved. In situations where the genetic variation is reduced in a population such as Danish Shorthorn, crossbreeding can be the only method to re-establish the genetic variation in the population, with the aim of recreating the sustainability of the breeding work (Kettunen et al., 2017; Lewis et al., 2015). It is necessary to act quickly regarding Danish Shorthorn. The possibility for gene renewal in Danish Shorthorn should therefore be examined as a preservation strategy.
The Shorthorn race originates from England, but spread out geographically to Northern Europe, America, Canada and Australia, among others. It became popular in Denmark in the late 19th century, mainly through imported animals from Ejderstedt in Germany, followed later by import from England (Sørensen and Nielsen, 2017). Supplementation of the genetic variation in Danish Shorthorn can therefore be done with animals of pure shorthorn pedigree, which are presumed to have donated genetic material, or to have an origin resembling Danish Shorthorn.
With financial support from The Danish Agricultural Agency under the Danish Ministry of Environment and Food, we have initiated the project Danish Shorthorn breeding in the Future – Genomic Mapping of Shorthorn populations (Dansk Korthornsavl i Fremtiden - Genomisk Kortlægning af Korthornspopulationer). Our goal is to map and compare the genetic variation and the relationship between the Danish population and foreign shorthorn populations in order to ensure a sustainable preservation effort of Danish Shorthorn in the future, with focus on potential gene renewal of the existing Danish Shorthorn population. By applying new technologies that use the variation in the genome, it is possible not only to determine the relationship between animals, but also to characterize genetic differences both between and within shorthorn populations. The genomic information will form the basis for the clarification of present relationships between the Danish population and the foreign shorthorn populations. The results of the genetic examinations will be used to trace potential unwanted mix in other shorthorn herds, so that mixed herds or animals can be excluded from import of genetic material. Furthermore, the information will be the basis for identification of suitable collaboration partners in sustainable preservation of Danish Shorthorn, particularly concerning potential gene renewals of the existing Danish Shorthorn, and without compromising the specific character of the Danish shorthorn population.
References
Szekeres, B.D.; Schönherz, A.A.; Nielsen, V.H.; Guldbrandtsen, B. 2016. Gamle Danske Husdyrracers Genomer – Racernes Oprindelse og Slægtskab; DCA Rapport, nr. 82, Aarhus University; ISBN: 978-87-93398-38-2. http://web.agrsci.dk/djfpublikation/djfpdf/DCArapport082.pdf
Kettunen, A.; Daverdin, M.; Helfjord, T.; Berg, P. 2017. Cross‐Breeding Is Inevitable to Conserve the Highly Inbred Population of Puffin Hunter: The Norwegian Lundehund; PLoS ONE 12(1):e0170039. https://doi.org/10.1371/journal.pone.0170039
Lewis, T.W.; Abhayaratne, B.M.; Blott, S.C. 2015. Trends in genetic diversity for all Kennel Club Registered pedigree dog breeds. Canine Genetics and Epidemiology 2:13 doi: 10.1186/s40575-015-0027-4
Sørensen, L.H.; Nielsen, V.H. 2017. Danske Husdyrgenetiske ressourcer. DCA rapport, nr. 100, Aarhus Universitet. ISBN: 978‐87‐93398‐78‐8. http://web.agrsci.dk/djfpublikation/djfpdf/DCArapport100b.pdf
