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Merino and Merino-derived sheep breeds: a genome-wide intercontinental study.

Ciani E, Lasagna E, D'Andrea M, Alloggio I, Marroni F, Ceccobelli S, Delgado Bermejo JV, Sarti FM, Kijas J, Lenstra JA, Pilla F, International Sheep Genomics Consorti - Genet. Sel. Evol. (2015)

Bottom Line: The Merino populations from Australia, New Zealand and China were clearly separated from their European ancestors.We observed a genetic substructuring in the Spanish Merino population, which reflects recent herd management practices.To explain how the current Merino and Merino-derived breeds were obtained, we propose a scenario that includes several consecutive migrations of sheep populations that may serve as working hypotheses for subsequent studies.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Bioscienze, Biotecnologie, Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A 70126, Bari, Italy. elena.ciani@uniba.it.

ABSTRACT

Background: Merino and Merino-derived sheep breeds have been widely distributed across the world, both as purebred and admixed populations. They represent an economically and historically important genetic resource which over time has been used as the basis for the development of new breeds. In order to examine the genetic influence of Merino in the context of a global collection of domestic sheep breeds, we analyzed genotype data that were obtained with the OvineSNP50 BeadChip (Illumina) for 671 individuals from 37 populations, including a subset of breeds from the Sheep HapMap dataset.

Results: Based on a multi-dimensional scaling analysis, we highlighted four main clusters in this dataset, which corresponded to wild sheep, mouflon, primitive North European breeds and modern sheep (including Merino), respectively. The neighbor-network analysis further differentiated North-European and Mediterranean domestic breeds, with subclusters of Merino and Merino-derived breeds, other Spanish breeds and other Italian breeds. Model-based clustering, migration analysis and haplotype sharing indicated that genetic exchange occurred between archaic populations and also that a more recent Merino-mediated gene flow to several Merino-derived populations around the world took place. The close relationship between Spanish Merino and other Spanish breeds was consistent with an Iberian origin for the Merino breed, with possible earlier contributions from other Mediterranean stocks. The Merino populations from Australia, New Zealand and China were clearly separated from their European ancestors. We observed a genetic substructuring in the Spanish Merino population, which reflects recent herd management practices.

Conclusions: Our data suggest that intensive gene flow, founder effects and geographic isolation are the main factors that determined the genetic makeup of current Merino and Merino-derived breeds. To explain how the current Merino and Merino-derived breeds were obtained, we propose a scenario that includes several consecutive migrations of sheep populations that may serve as working hypotheses for subsequent studies.

No MeSH data available.


Related in: MedlinePlus

a Genetic structure and admixture plot for all breeds analyzed in this study based on coefficients of individual membership to clusters (K) assumed to be present in the complete sample. b Zoomed detail of the genetic structure and admixture plot for the Spanish Merino breed
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Fig3: a Genetic structure and admixture plot for all breeds analyzed in this study based on coefficients of individual membership to clusters (K) assumed to be present in the complete sample. b Zoomed detail of the genetic structure and admixture plot for the Spanish Merino breed

Mentions: Model-based clustering was performed to search for admixture and genetic distinctiveness between breeds and breed groups. The plot obtained by ADMIXTURE analysis is in Fig. 3a, which shows the results for K (number of clusters assumed in the whole sample) ranging from 2 to 37. At K = 2, the first populations to be differentiated are the Sardinian and the European mouflon, which display a similar pattern of genetic differentiation that confirms the hypothesis of mutual introgression between the Sarda breed and the Sardinian mouflon [4]. At K = 4, four distinct genetic components are clearly observed: the three wild sheep (O. orientalis, O. ammon, and O. vignei), the mouflon, the primitive Soay and Boreray breeds, and the modern breeds. At K = 10, a Merino genetic component is detected that is shared by the three Australian Merino populations, most of the Merino-derived breeds (Rambouillet, Chinese Merino, Merinolandschaf, and Merinizzata Italiana), Spanish Merino and, partially, by the four Spanish non-Merino breeds (Churra, Ojalada, Rasa Aragonesa, and Castellana) and the Italian Merino-derived breeds Gentile di Puglia and Sopravissana. Another major component is shared by the Italian breeds Massese, Appenninica, Laticauda, Leccese, Comisana, and Sardinian White (also influenced by the Sardinian mouflon), and, partially, by the Gentile di Puglia, Sopravissana, the four Spanish non-Merino breeds, Merinizzata Italiana, Spanish Merino and Merinolandschaf breeds. At K values higher than 10, the three Australian Merino populations form a separate cluster and more and more breeds are differentiated.Fig. 3


Merino and Merino-derived sheep breeds: a genome-wide intercontinental study.

Ciani E, Lasagna E, D'Andrea M, Alloggio I, Marroni F, Ceccobelli S, Delgado Bermejo JV, Sarti FM, Kijas J, Lenstra JA, Pilla F, International Sheep Genomics Consorti - Genet. Sel. Evol. (2015)

a Genetic structure and admixture plot for all breeds analyzed in this study based on coefficients of individual membership to clusters (K) assumed to be present in the complete sample. b Zoomed detail of the genetic structure and admixture plot for the Spanish Merino breed
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4536749&req=5

Fig3: a Genetic structure and admixture plot for all breeds analyzed in this study based on coefficients of individual membership to clusters (K) assumed to be present in the complete sample. b Zoomed detail of the genetic structure and admixture plot for the Spanish Merino breed
Mentions: Model-based clustering was performed to search for admixture and genetic distinctiveness between breeds and breed groups. The plot obtained by ADMIXTURE analysis is in Fig. 3a, which shows the results for K (number of clusters assumed in the whole sample) ranging from 2 to 37. At K = 2, the first populations to be differentiated are the Sardinian and the European mouflon, which display a similar pattern of genetic differentiation that confirms the hypothesis of mutual introgression between the Sarda breed and the Sardinian mouflon [4]. At K = 4, four distinct genetic components are clearly observed: the three wild sheep (O. orientalis, O. ammon, and O. vignei), the mouflon, the primitive Soay and Boreray breeds, and the modern breeds. At K = 10, a Merino genetic component is detected that is shared by the three Australian Merino populations, most of the Merino-derived breeds (Rambouillet, Chinese Merino, Merinolandschaf, and Merinizzata Italiana), Spanish Merino and, partially, by the four Spanish non-Merino breeds (Churra, Ojalada, Rasa Aragonesa, and Castellana) and the Italian Merino-derived breeds Gentile di Puglia and Sopravissana. Another major component is shared by the Italian breeds Massese, Appenninica, Laticauda, Leccese, Comisana, and Sardinian White (also influenced by the Sardinian mouflon), and, partially, by the Gentile di Puglia, Sopravissana, the four Spanish non-Merino breeds, Merinizzata Italiana, Spanish Merino and Merinolandschaf breeds. At K values higher than 10, the three Australian Merino populations form a separate cluster and more and more breeds are differentiated.Fig. 3

Bottom Line: The Merino populations from Australia, New Zealand and China were clearly separated from their European ancestors.We observed a genetic substructuring in the Spanish Merino population, which reflects recent herd management practices.To explain how the current Merino and Merino-derived breeds were obtained, we propose a scenario that includes several consecutive migrations of sheep populations that may serve as working hypotheses for subsequent studies.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Bioscienze, Biotecnologie, Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A 70126, Bari, Italy. elena.ciani@uniba.it.

ABSTRACT

Background: Merino and Merino-derived sheep breeds have been widely distributed across the world, both as purebred and admixed populations. They represent an economically and historically important genetic resource which over time has been used as the basis for the development of new breeds. In order to examine the genetic influence of Merino in the context of a global collection of domestic sheep breeds, we analyzed genotype data that were obtained with the OvineSNP50 BeadChip (Illumina) for 671 individuals from 37 populations, including a subset of breeds from the Sheep HapMap dataset.

Results: Based on a multi-dimensional scaling analysis, we highlighted four main clusters in this dataset, which corresponded to wild sheep, mouflon, primitive North European breeds and modern sheep (including Merino), respectively. The neighbor-network analysis further differentiated North-European and Mediterranean domestic breeds, with subclusters of Merino and Merino-derived breeds, other Spanish breeds and other Italian breeds. Model-based clustering, migration analysis and haplotype sharing indicated that genetic exchange occurred between archaic populations and also that a more recent Merino-mediated gene flow to several Merino-derived populations around the world took place. The close relationship between Spanish Merino and other Spanish breeds was consistent with an Iberian origin for the Merino breed, with possible earlier contributions from other Mediterranean stocks. The Merino populations from Australia, New Zealand and China were clearly separated from their European ancestors. We observed a genetic substructuring in the Spanish Merino population, which reflects recent herd management practices.

Conclusions: Our data suggest that intensive gene flow, founder effects and geographic isolation are the main factors that determined the genetic makeup of current Merino and Merino-derived breeds. To explain how the current Merino and Merino-derived breeds were obtained, we propose a scenario that includes several consecutive migrations of sheep populations that may serve as working hypotheses for subsequent studies.

No MeSH data available.


Related in: MedlinePlus