Genetic diversity of Ovis aries populations near domestication centers and in the New World

Abstract

Domestic sheep in Kazakhstan may provide an interesting source of genetic variability due to their proximity to the center of domestication and the Silk Route. Additionally, those breeds have never been compared to New World sheep populations. This report compares genetic diversity among five Kazakhstan (KZ) and 13 United States (US) sheep breeds (N = 442) using 25 microsatellite markers from the FAO panel. The KZ breeds had observed and expected measures of heterozygosity greater than 0.60 and an average number of alleles per locus of 7.8. In contrast, US sheep breeds had observed heterozygosity ranged from 0.37 to 0.62 and had an average number of alleles of 5.7. A Bayesian analysis indicated there were two primary populations (K = 2). Surprisingly, the US breeds were near evenly split between the two clusters, while all of the KZ breeds were placed in one of the two clusters. Pooling breeds within country of sample origin showed KZ and US populations to have similar levels of expected heterozygosity and the average number of alleles per locus. The results of breeds pooled within country suggest that there was no difference between countries for these diversity measures using this set of neutral markers. This finding suggests that populations' geographically isolated from centers of domestication can be more diverse than previously thought, and as a result, conservation strategies can be adjusted accordingly. Furthermore, these results suggest there may be limited need for countries to alter the protocols for trade and exchange of animal genetic resources that are in place today, since no one population has a unique set of private alleles.

Genetic diversity of Colombian sheep by microsatellite markers

“…The highest number of alleles per locus was found in the creole hair sheep or CAM (11.91 alleles per locus), value that is higher than the 7.80 alleles per locus reported by Quiroz et al (2007) in Mexican creole sheep, 7.25 alleles per locus reported by Ochipinti et al (2012) in Paraguayan creole sheep, and 7.71 alleles per locus reported by Blackburn et al (2011) in North American creole sheep. However, we should consider that the high number of alleles found in the Colombian CAM may have arisen as a result of having taken samples of 292 individuals, which represent 53.18% of all individuals in the sample and it is because this breed is the most representative and common within the country since CAM represent over 50% of the national sheep inventory (Arcos et al, 2002).…”

Genetic characterization of Colombian indigenous sheep

“…The OPC breed had the highest MNA (12.40), which in turn is higher than the value reported in Mexican indigenous sheep (7.8 alleles/locus; Quiroz et al (2007), Paraguayan indigenous sheep (7.25 alleles/locus; Ochipinti et al (2012), American indigenous sheep (7.71 alleles/locus; Blackburn et al (2011), Kenyan indigenous sheep (6.16 alleles/locus; Muigai et al (2009), and Indian indigenous sheep (5.48 alleles/locus; Arora et al (2010). It is important to note that OPC individuals represented 80.66% of the total population sampled, however, this percentage is similar to the proportion of this breed in the sheep national inventory (Martinez et al, 2009).…”

Contribution of microsatellites markers in the clarification of the origin, genetic risk factors, and implications for conservation of Tunisian native sheep breeds

“…Lowest heterozygosity and greatest inbreeding coefficient (F IS ) values exhibited by CRO population are shown in bold font. In general, the analyzed populations showed reasonably high allelic richness and heterozygosity values compared to some African (Soma et al, 2012;Kunene et al, 2014;Mukhongo et al, 2014), European (Salamon et al, 2014), Asian (Al-Barzinji et al, 2011;Blackburn et al, 2011b), and American (Blackburn, et al, 2011a;Souza et al, 2012;Ferreira et al, 2014) sheep breeds. The lowest values of AR and heterozygosity were observed in the crossbred population in which H O was notably lower than the H E (Table 2).…”