Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Autriche → Genetic diversity and admixture analysis of Ethiopian fat-tailed and Awassi sheep using SNP markers for designing crossbreeding schemes

Universität für Bodenkultur Wien (2015)

Genetic diversity and admixture analysis of Ethiopian fat-tailed and Awassi sheep using SNP markers for designing crossbreeding schemes

Mengistu, Tesfaye Getachew

Titre : Genetic diversity and admixture analysis of Ethiopian fat-tailed and Awassi sheep using SNP markers for designing crossbreeding schemes

Auteur : Mengistu, Tesfaye Getachew

Université de soutenance : Universität für Bodenkultur Wien

Grade : Dr. nat. techn. 2015

Résumé
The aims of this study were to identify small cost effective set of SNP markers for estimation of admixture level and to identify optimal levels of Awassi admixture for the on-going Awassi sheep crossbreeding program that has been implemented in Ethiopia. Improved Awassi sheep has been used to improve Ethiopian Menz and Wollo sheep breeds through crossbreeding in Negasi-Amba and Chiro villages. High density 50KSNPs distributed along the ovine genome was analyzed for the ancestral sheep breeds to assess genetic diversity, population structure, linkage disequilibrium and levels of inbreeding. Diversity was highest for local Awassi breeds followed by the two Ethiopian breeds. Strong selection pressure to improve productivity significantly differentiated improved Awassi from local Awassi. Low level of genetic variability and highest inbreeding level observed within the improved Awassi sheep breed should be noted and steps toward increasing diversity should take in to consideration. Awassi levels were estimated accurately from admixed individuals using 74 top FST ranked ancestry informative markers (AIMs). Top 45 AIMs were also gave similar result with the top 74 AIMs hence about 45 AIMs would be enough for accurate estimation of the level of ancestry. Association analysis of Awassi levels with performances suggests crossbreeding of Wollo sheep with Awassi in Chiro and similar areas up to 50% Awassi level and strengthening the ongoing selective pure breeding programs of Menz sheep in Negasi-Amba village. Considering the genetic variation created in the crossbred populations, genetic improvement applying continuous selection within the crossbred population along with improved management progressively leads to the development of a composite population should be considered. The use of AIMs would inspire livestock breeding programs in developing countries by availing breed composition and pedigree information which persisted as marked constraint

Mots clés : Admixtur / Äthiopien / Kreuzungszucht / Menz / Schafzucht / Wollo — Admixture / Awassi / crossbreeding / Ethiopia / Menz / sheep / Wollo

Présentation )

Version intégrale

Page publiée le 19 décembre 2015, mise à jour le 29 décembre 2017