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United States Department of Agriculture

Agricultural Research Service

Title: Genetic Diversity and Relationships of Hair Sheep Breeds of the Americas: First Results

Authors
item Muigai, A. - ILRI
item Hirbo, - ILRI
item Rege, J.E. - ILRI
item Sharkey, - CSU-STUDENT
item Blackburn, Harvey
item Hanotte, - ILRI

Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings
Publication Acceptance Date: May 1, 2002
Publication Date: August 1, 2002
Citation: Muigai, A.W., Hirbo, .J., Rege, J.0., Sharkey, .S., Blackburn, H.D., Hanotte, .O. 2002. Genetic diversity and relationships of hair sheep breeds of the americas: first results. World Congress of Genetics Applied in Livestock Production. 33:573-576.

Interpretive Summary: Understanding genetic differences between breeds is an important component of conserving genetic resources. Microsatellite markers are one tool that can be used to make an assessment of the genetic distance/diversity between breeds. We used this approach to determine the genetic distance between two major types of sheep found in the Americas, hair and wooled sheep. It has been commonly thought that hair breeds of sheep imported into the new world came from Africa via the Canary Islands, and wooled breeds were imported directly from Europe. Wooled (Rambouillet and Gulf Coast Native) and haired (Barbados Blackbelly and St. Croix) sheep from the U.S. and Caribbean were compared to a total of 12 African, Asian and European breeds using 14 mircosatellite markers. Based upon the microsatellite markers, it appears that the origin for haired and wooled sheep breeds tested was Europe and not Africa. This results bring into question previously held believes about the origin of hair sheep in the Americas. Therefore, a more comprehensive study using more populations should better clarify the origin and diversity of sheep genetic resources in the Americas.

Technical Abstract: There are two major types of sheep in the Americas, wooled and hair sheep. Such phenotypic differences bring into question an African or European origin for these types of sheep. It has been commonly thought that hair breeds of sheep imported into the new world came from Africa via the Canary Islands and wooled breeds were imported directly from Europe. Molecular markers provide a tool for testing such long held views and measuring the genetic diversity between breeds. Wooled (Rambouillet and Gulf Coast Native) and haired (Barbados Blackbelly and St. Croix) sheep from the US and Caribbean were compared to a total of 12 African, Asian and European breeds using 14 mircosatellite markers. Between breed genetic relationships were calculated using Nei's genetic distance (Da) and a neighbor-joining tree was constructed. Rambouillet, as expected, was closely related to Portuguese Black Merino and Portuguese White Merino. The St. Croix, Barbados Blackbelly and Gulf Coast Native were most closely related to the two Portuguese breeds, this result was not anticipated. These results suggest that the major genetic influence in the American breeds evaluated is likely European, with a prevalence of Merino. The study of more populations should better clarify the origin and diversity of genetic resources present in the Americas.

Last Modified: 10/25/2014
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