|HUSON, HEATHER - Cornell University|
|GODFREY, JAMES - Royal Jersey Agricultural & Horticultural Society|
|HAMBROOK, DAVID - Royal Jersey Agricultural & Horticultural Society|
|WOLFE, CARI - American Jersey Cattle Association|
|Van Tassell, Curtis - Curt|
Submitted to: Frontiers in Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2020
Publication Date: 4/17/2020
Citation: Huson, H.J., Sonstegard, T.S., Godfrey, J., Hambrook, D., Wolfe, C., Wiggans, G.R., Blackburn, H.D., Van Tassell, C.P. 2020. A genetic investigation of Island of Jersey cattle, the foundation of the Jersey breed. Frontiers in Genetics. 11:366. https://doi.org/10.3389/fgene.2020.00366.
Interpretive Summary: Livestock breeds are frequently imported and exported to various parts of the world. These importations are just a sample of the breed in its country of origin. Therefore an important question is how different are global populations from the founder population. Jersey cattle have been widely exported from there geographic origin, Isle of Jersey, however until recently the Isle of Jersey never allowed any re-importation of Jersey cattle. This research was largely driven by Island of Jersey legislation opening the Island of Jersey to germplasm importation in an effort to understand the foundation stock of Jersey cattle and future implications of gene flow plus how the U. S. population has deviated from the founding population. Surprisingly the inbreeding level between the two populations was similar despite the large number of Jersey in the U.S. (more than 30 times as large). Principal component analysis indicated that Isle of Jersey and U.S. populations were placed in close proximity with one another when compared to Guernsey (another island breed) and Holstein. This suggests the two populations remained very similar despite a relatively long period of segregation. That said, different chromosomes exhibited varying amount of homozygosity. The results provide a genetic baseline to monitor changes in the Jersey genome both on the Isle of Jersey and in the U.S.
Technical Abstract: For two centuries, Jersey cattle were exported globally, adapting to varying climates and production systems, yet the founding population remained genetically isolated on the Island of Jersey. Cryopreservation of Island of Jersey cattle germplasm opened the doors to genetic importation in 2008. This study characterized the genetic variation of popular Island Jersey bulls from 1964-2004 and compared them with non-Island Jersey primarily from the U.S. In addition, Guernsey cattle deriving from the Island of Guernsey, and Holstein cattle served as reference populations for genetic evaluation. Principal component analysis indicated population stratification reflective of individual animal’s continental origin yet overall Jersey breed clustering in comparison to Holstein and Guernsey. The Jersey breed demonstrated increased inbreeding in comparison to Holstein or Guernsey with an excess of short-range runs of homozygosity (ROH). Surprisingly, the Island and U.S. Jersey have relatively similar inbreeding estimates despite vastly different population sizes and gene flow. Signatures of selection were identified using genome-wide homozygosity association and marker-based FST which provided population informative single-nucleotide polymorphism (SNPs). Biological significance of the homozygosity association results identified multiple genes on chromosomes 5, 24, and 27, involved in immune function and cellular processes within Island Jersey. Overall, this research provides a reference study for the Jersey breed based on the genetic foundation of the Island cattle as compared to the intensively selected U.S. cattle. Genomic variation was identified between the Island and non-Island Jersey cattle producing population informative SNPs and differing runs of homozygosity over immune regulation and metabolic genes. Further investigation is needed to discern the benefits of these conserved regions and their potential influence on adaptive traits respective to production systems. This study provides the framework for future investigation of health traits and management decisions for Island Jerseys including germplasm regulations and breed conservation.