Genetic diversity estimates point to immediate efforts for conserving the endangered Tibetan sheep of India

Abstract

Tibetan is a valuable Himalayan sheep breed classified as endangered. Knowledge of the level and distribution of genetic diversity in Tibetan sheep is important for designing conservation strategies for their sustainable survival and to preserve their evolutionary potential. Thus, for the first time, genetic variability in the Tibetan population was accessed with twenty five inter-simple sequence repeat markers. All the microsatellites were polymorphic and a total of 148 alleles were detected across these loci. The observed number of alleles across all the loci was more than the effective number of alleles and ranged from 3 (BM6506) to 11 (BM6526) with 5.920 ± 0.387 mean number of alleles per locus. The average observed heterozygosity was less than the expected heterozygosity. The observed and expected heterozygosity values ranged from 0.150 (BM1314) to 0.9 (OarCP20) with an overall mean of 0.473 ± 0.044 and from 0.329 (BM8125) to 0.885 (BM6526) with an overall mean 0.672 ± 0.030, respectively. The lower heterozygosity pointed towards diminished genetic diversity in the population. Thirteen microsatellite loci exhibited significant (P < 0.05) departures from the Hardy–Weinberg proportions in the population. The estimate of heterozygote deficiency varied from − 0.443 (OarCP20) to 0.668 (OarFCB128) with a mean positive value of 0.302 ± 0.057. A normal ‘L’ shaped distribution of mode-shift test and non-significant heterozygote excess on the basis of different models suggested absence of recent bottleneck in the existing Tibetan population. In view of the declining population of Tibetan sheep (less than 250) in the breeding tract, need of the hour is immediate scientific management of the population so as to increase the population hand in hand with retaining the founder alleles to the maximum possible extent.

The genetic diversity and population structure of shallots (Allium cepa var. aggregatum) in Indonesia based on R gene-derived markers

“…Selection of R genederived markers with a range of polymorphisms may reduce the risk of overestimating genetic variability. This is in agreement with a study on genetic diversity using microsatellite markers in sheep as reported by Sharma et al (2016).…”

Assessment of genetic diversity and structure of major sheep breeds from Pakistan

“…As part of this program, the present study was undertaken with the objectives of evaluating diversity and genetic relationship of five economically important sheep breeds of Pakistan, Balkhi, Damani, Kaghani, Salt Range and Thalli. The results of the present work will help to better understand the current genetic diversity in these breeds, and contribute towards formulating effective strategies for prioritization, conservation and genetic improvement of indigenous sheep breeds in Pakistan (Gaouar et al, 2015;Guang-Xin et al, 2016;Sharma et al, 2016).…”

Genetic variability in a population of Letelle sheep in South Africa

“…Paiva et al (2011b) used US and Brazilian datasets and determined F IS values ranging from -10.7% and 32.6%. Such heterozygote deficiency has been observed in Indian breeds, including Magra (15.9%) (Arora & Bhatia, 2006), Muzzafarnagri (5.8%) (Arora & Bhatia, 2004), Shahabadi (21.5%) (Panday et al, 2010), Tibetan (30.2%) (Sharma et al, 2016), Vembur (29.4%) (Pramod et al, 2009), Sarda sheep from Italy (19%) (Pariset et al, 2003) and 29 European sheep breeds (mean of 12.1%) (Lawson Handley et al, 2007).…”