Globally dispersed Y chromosomal haplotypes in wild and domestic sheep

Abstract

To date, investigations of genetic diversity and the origins of domestication in sheep have utilised autosomal microsatellites and variation in the mitochondrial genome. We present the first analysis of both domestic and wild sheep using genetic markers residing on the ovine Y chromosome. Analysis of a single nucleotide polymorphism (oY1) in the SRY promoter region revealed that allele A-oY1 was present in all wild bighorn sheep (Ovis canadensis), two subspecies of thinhorn sheep (Ovis dalli), European Mouflon (Ovis musimon) and the Barbary (Ammontragis lervia). A-oY1 also had the highest frequency (71.4%) within 458 domestic sheep drawn from 65 breeds sampled from Africa, Asia, Australia, the Caribbean, Europe, the Middle East and Central Asia. Sequence analysis of a second locus, microsatellite SRYM18, revealed a compound repeat array displaying fixed differences, which identified bighorn and thinhorn sheep as distinct from the European Mouflon and domestic animals. Combined genotypic data identified 11 male-specific haplotypes that represented at least two separate lineages. Investigation of the geographical distribution of each haplotype revealed that one (H6) was both very common and widespread in the global sample of domestic breeds. The remaining haplotypes each displayed more restricted and informative distributions. For example, H5 was likely founded following the domestication of European breeds and was used to trace the recent transportation of animals to both the Caribbean and Australia. A high rate of Y chromosomal dispersal appears to have taken place during the development of domestic sheep as only 12.9% of the total observed variation was partitioned between major geographical regions.

Y chromosome haplotype characterization of Tunisian sheep breeds

“…Several studies have shown that H6 is the most predominant haplotype in different sheep breeds (12,14,(23)(24)(25), except for the Tyrolean Mountain sheep (Austria) and Brown and White Mountain sheep (Germany) that exhibited only the H8 haplotype (12). In this regard, African breeds also showed a higher frequency for the H6 haplotype (66.6%) (13), while in this study the H8 haplotype is the most frequently observed (55.5%).…”

“…Interestingly, this haplotype was found in the Western Thin Tail. The H5 haplotype has been observed in European (19%) and Australian (27.2%) sheep (13), as well as in Asian and Caribbean (12,13) breeds, but it was absent in all African breeds analyzed so far. In this study, this haplotype was detected only in the Black Thibar breed, which could be explained by the (Figure 2), suggesting possible genetic admixture as a result of uncontrolled reproduction.…”

“…To accurately determine the allele size, a sample from the Spanish Rasa Aragonesa breed, previously validated as 141 bp by Meadows et al (12), was also included in each run. PCR amplifications of two 5'-upstream regions (549 and 598 bp in length) of the SRY gene and a fragment of the 3'-untranslated region of the DBY gene (171 bp) were carried out as described by Meadows et al (18).…”

“…Thus, these markers have been used to study malespecific gene flow to gain insight into the species' history, particularly admixture between populations, migration, and other events (11). Several studies have investigated this type of genetic system in sheep (12)(13)(14).…”

Genetic Characterization of Albanian Sheep Breeds by Microsatellite Markers

“…Microsatellites are used, in livestock species for estimating genetic variation within and among breeds (Buchanan et al, 1994;Cronin et al, 2009;Diez-Tascon et al, 2000a;Dowling et al, 2008;Schmid et al, 1999;Saitbekova et al, 1999), for admixture studies (Alvarez et al, 2004;Freeman et al, 2004Freeman et al, , 2006MacHugh et al, 1997;Vicente et al, 2008) and for assigning individuals to breeds (Baumung et al, 2006;Cornuet et al, 1999;Maudet et al, 2002;Meadows et al, 2006;Troy et al, 2001). …”