Genetic Distinctiveness of the Herdwick Sheep Breed and Two Other Locally Adapted Hill Breeds of the UK

Abstract

There is considerable interest in locally adapted breeds of livestock as reservoirs of genetic diversity that may provide important fitness traits for future use in agriculture. In marginal areas, these animals contribute to food security and extract value from land unsuitable for other systems of farming. In England, close to 50% of the national sheep flock is farmed on grassland designated as disadvantaged areas for agricultural production. Many of these areas are in the uplands, where some native breeds of sheep continue to be commercially farmed only in highly localised geographical regions to which they are adapted. This study focuses on three of these breeds, selected for their adaptation to near identical environments and their geographical concentration in regions close to one another. Our objective has been to use retrotyping, microsatellites and single nucleotide polymorphisms to explore the origins of the breeds and whether, despite their similar adaptations and proximity, they are genetically distinctive. We find the three breeds each have a surprisingly different pattern of retrovirus insertions into their genomes compared with one another and with other UK breeds. Uniquely, there is a high incidence of the R0 retrotype in the Herdwick population, characteristic of a primitive genome found previously in very few breeds worldwide and none in the UK mainland. The Herdwick and Rough Fells carry two rare retroviral insertion events, common only in Texels, suggesting sheep populations in the northern uplands have a historical association with the original pin-tail sheep of Texel Island. Microsatellite data and analyses of SNPs associated with RXFP2 (horn traits) and PRLR (reproductive performance traits) also distinguished the three breeds. Significantly, an SNP linked to TMEM154, a locus controlling susceptibility to infection by Maedi-Visna, indicated that all three native hill breeds have a lower than average risk of infection to the lentivirus.

Molecular identification of livestock breeds: a tool for modern conservation biology

“…This revolution is expedited by the concomitant advancement in bioinformatics tools and pipelines (Kofler, Nolte & Schlötterer, 2015). DNA markers have been used not only for diversity studies but also for molecular characterisation of numerous livestock breeds worldwide (Agaviezor et al, 2012;Al-Atiyat, Salameh & Tabbaa, 2014;Alvarez et al, 2012;Bowles et al, 2014). The dramatic reduction in the cost of use of DNA markers has facilitated their greater use by researchers.…”

Conservation genetics in Chinese sheep: diversity of fourteen indigenous sheep (Ovis aries) using microsatellite markers

“…However, commercial lines and industrialized livestock production systems have spread over all continents resulting in decreasing of large indigenous sheep breeds in comparison with some commercial breeds. Many studies have assessed the diversity of native local sheep in India (Dorji et al 2010;Pandey et al 2010;Arora et al 2011), the Middle East and Europe (Alvarez et al 2005;Lawson Handley et al 2007;Peter et al 2007;Zahedi-Zahra et al 2007;Dalvit et al 2009;Glowatzki-Mullis et al 2009;Bowles et al 2014;Yilmaz et al 2014;Pons et al 2015), Eurasia (Blackburn et al 2011a;Paiva et al 2011a,b;Salamon et al 2014), America Paiva et al 2011a,b;Souza et al 2012;Crispim et al 2013;Ferreira et al 2014), and Africa (Gizaw et al 2007;Agaviezor et al 2012;Qwabe et al 2013;Gaouar et al 2015).…”

Endogenous Retroviral Insertions Indicate a Secondary Introduction of Domestic Sheep Lineages to the Caucasus and Central Asia between the Bronze and Iron Age

“…The greater diversity is a result of higher frequencies of enJSRV-7 and lower frequencies of enJSRV-18 compared to modern samples. As noted in this regard they resemble primitive North European breeds [22,30,31]. These breeds are characterized by coarse wool that still possesses larger quantities of guard hair than the wool of economically important merino breeds.…”

“…As mentioned before in marginal areas of northern Europe older Bronze Age sheep lineages endured until today [22,30,31,32]. Since the improved wool lineages likely originated in the Middle East [30] and were initially more productive in a warm and dry climate, it is possible that they were unable to compete with the cold and wet climate-adapted European Bronze Age lineages in the harsher conditions of northern Europe.…”