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Title: Genetic diversity of Ovis aries populations near domestication centers and in the new world

Author
item Blackburn, Harvey
item TOISHIBEKOV, Y - Institute Of Experimental Biology
item TOISHIBEKOV, M - Institute Of Experimental Biology
item Wilson, Carrie - Welsh
item Spiller, Scott
item Brown, Michael
item PAVIA, SAMULE - Embrapa-Labex

Submitted to: Genetica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2011
Publication Date: 12/22/2011
Citation: Blackburn, H.D., Toishibekov, Y., Toishibekov, M., Welsh, C.S., Spiller, S.F., Brown, M.A., Pavia, S. 2011. Genetic diversity of Ovis aries populations near domestication centers and in the new world. Genetica. 139:1169-1178.

Interpretive Summary: Since the 1950’s the U. S. domestic sheep population has experienced a dramatic decreased in size which in turn raises concerns about remaining levels of genetic diversity to utilize in future sheep production strategies. It is commonly believed that animal populations at or near centers of domestication have greater levels of genetic diversity and therefore comparing U. S. sheep populations to such populations could provide insights to possible levels of genetic contraction. Therefore, 13 U. S. breeds were compared to 5 breeds from Kazakhstan using a commonly used set of genetic markers. The results indicated that at the individual breed level the Kazakh populations had greater genetic diversity measures. However, when the samples were pooled across breed within country it was determined that there were no differences in genetic diversity measures for sheep in the U. S. and Kazakhstan. This finding suggests substantial genetic diversity is present within the U. S. sheep population. In addition it suggests that populations geographically distance from centers of domestication can be more diverse than previously thought and as a result conservation strategies can be adjusted accordingly. Furthermore, the results have implications for international negotiations concerning the access and benefit sharing of genetic resources.

Technical Abstract: Domestic sheep in Kazakhstan may provide an interesting source of genetic variability due to their proximately 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 the FAO panel of 29 microsatellite markers. The KZ breeds had observed and expected measures of heterozgosity greater than 0.60, and an average number of alleles per locus of 7.8. Contrastingly, US observed heterozgosity ranged from 0.37 to 0.62 and had an average number of alleles of 5.7. The Bayesian analysis shows that fat-rumped KZ breeds Chuisk, Degresskaya, Edil’baevskaya, Sary-Arka were placed in one cluster and the Arkhara-Merino was placed in a cluster containing Rambouillet and Tunis breeds. When the data from each country’s breeds were pooled together the within breed genetic diversity analyses showed KZ and US populations to have similar levels of expected heterozgosity and the average number of alleles per locus. Correlation of allele frequencies within locus between the two countries was 0.86 suggesting that the distribution of alleles within locus were similar. 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 distance from centers of domestication can be more diverse than previously thought and as a result conservation strategies can be adjusted accordingly.