Genetic diversity, structure, and breed relationships in Iberian cattle.

In Iberia there are 51 officially recognized cattle breeds of which 15 are found in Portugal and 38 in Spain. We present here a comprehensive analysis of the genetic diversity and structure of Iberian cattle. Forty of these breeds were genotyped with 19 highly polymorphic microsatellite markers. Asturiana de los Valles displayed the greatest allelic diversity and Mallorquina the least. Unbiased heterozygosity values ranged from 0.596 to 0.787. The network based on Reynolds distances was star-shaped with few pairs of interrelated breeds and a clear cluster of 4 breeds (Alistana/Arouquesa/Marinhoa/Mirandesa). The analysis of the genetic structure of Iberian cattle indicated that the most probable number of population clusters included in the study would be 36. Distance results were supported by the STRUCTURE software indicating a relatively recent origin or possible crossbreeding or both between pairs or small groups of breeds. Five clusters included 2 different breeds (Betizu/Pirenaica, Morucha/Avileña, Parda de Montaña/Bruna de los Pirineos, Barrosã/Cachena, and Toro de Lidia/Brava de Lide), 3 breeds (Berrenda en Negro, Negra Andaluza, and Mertolenga) were divided in 2 independent clusters each, and 2 breeds were considered admixed (Asturiana de los Valles and Berrenda en Colorado). Individual assignation to breeds was not possible in the 2 admixed breeds and the pair Parda de Montaña/Bruna de los Pirineos. The relationship between Iberian cattle reflects their geographical origin rather than their morphotypes. Exceptions to this geographic clustering are most probably a consequence of crossbreeding with foreign breeds. The relative genetic isolation within their geographical origin, the consequent genetic drift, the adaptation to specific environment and production systems, and the influence of African and European cattle have contributed to the current genetic status of Iberian cattle, which are grouped according to their geographical origin. The greater degree of admixture observed in some breeds should be taken into account before using molecular markers for genetic assignment of individuals to breeds.

Martín-Burriel I ，Rodellar C ，Cañón J ，Cortés O ，Dunner S ，Landi V ，Martínez-Martínez A ，Gama LT ，Ginja C ，Penedo MC ，Sanz A ，Zaragoza P ，Delgado JV ... -  《-》

Genetic diversity and differentiation in Portuguese cattle breeds using microsatellites.

Genotype data from 30 microsatellites were used to assess genetic diversity and relationships among 10 native Portuguese cattle breeds, American Charolais and the Brazilian Caracú. Hardy-Weinberg equilibrium was observed for all loci/population combinations except for five loci in Brava de Lide and one locus in Alentejana that exhibited heterozygote deficiency. Estimates of average observed and expected heterozygosities, total number of alleles (TNA) per breed and mean number of alleles (MNA) per locus/population were obtained. A total of 390 alleles were detected. TNA among Iberian cattle ranged from 170 to 237 and MNA ranged from 5.67 to 8.07. The highest observed heterozygosities were found in the Caracú, Maronesa, Garvonesa and Arouquesa and the lowest in Brava de Lide and Mirandesa. Estimation of population subdivision using Wright's FST index showed that the average proportion of genetic variation explained by breed differences was 9%. Neighbour-joining phylogenetic trees based on DA distances showed that the genetic relationships of present-day Portuguese native breeds are consistent with historical origins in the Brown Concave (Arouquesa, Mirandesa, Marinhoa) and Red Convex (Mertolenga, Alentejana, Garvonesa, Minhota) evolutionary groups. The Iberian Black Orthoide group, represented by Brava de Lide and Maronesa, and the Barrosã breed appeared to be more closely related to the Brown Concave group but may represent a separate lineage. The Caracú breed was not found to be closely associated with any of the native Portuguese breeds.

Mateus JC ，Penedo MC ，Alves VC ，Ramos M ，Rangel-Figueiredo T ... -  《ANIMAL GENETICS》

Analysis of STR markers reveals high genetic structure in Portuguese native cattle.

Genetic structure and diversity of 13 Portuguese native and 3 imported cattle breeds were assessed with 39 microsatellites. Allelic richness per locus was high, with an overall average of 8.3 +/- 2.5. The mean observed and expected heterozygosities were 0.673 +/- 0.043 and 0.691 +/- 0.034, respectively. The mean number of alleles per breed ranged between 5.36 +/- 1.27 and 7.87 +/- 2.66. Brava de Lide and Mirandesa breeds had the lowest genetic diversity, whereas Minhota, Arouquesa, and Mertolenga had the highest. Significant (P < 0.05) heterozygote deficit was detected in all breeds except Garvonesa, Marinhoa, Minhota, and Limousin. Hardy-Weinberg deviations are most probably due to inbreeding, particularly in Alentejana, Brava de Lide, Mertolenga, and Ramo Grande (F(is) > 0, P < 0.0001). Based on the principal component and the Neighbor-Net analyses, Mirandesa was the most genetically distinct breed. Even though admixture was detected across all breeds (6.7%, q < 0.800), the molecular structure was consistent with original breed designations, with the exception of Cachena that had a clear influence of Barrosã (K = 15). Mertolenga showed substructure with independent clustering of red speckled animals. The percentage animals correctly assigned was >or=90 in all breeds except Cachena, Garvonesa, and Preta (q >or= 0.800). The results obtained here confirmed that high levels of genetic diversity exist within Portuguese native cattle and that the breeds are highly structured. Conservation measures should be implemented for all native breeds to minimize inbreeding.

Ginja C ，Telo Da Gama L ，Penedo MC 《-》

Genetic diversity and relationships of endangered Spanish cattle breeds.

Information on the genetic structure and variability of autochthonous livestock breeds is essential for effective conservation programs. Here we present a molecular characterization on the basis of 30 microsatellite markers of 5 Spanish endangered cattle breeds Betizu (BET), Mallorquina (MAL), Menorquina, Monchina (MON), and Serrana de Teruel (ST) and of 2 fighting bull populations, Casta Navarra (CN) and Casta Vistahermosa. The feral and critically endangered BET is divided into 2 subpopulations, one of which has exceptionally low diversity values. A low number of alleles was also observed in the island population MAL. Although the small population size and genetic drift have caused a considerable divergence between the breeds, phylogenetic analysis is in accordance with historical and geographical data. The 2 northern Spanish feral breeds BET and MON cluster together. The local fighting breed CN is relatively close to the more inbred Casta Vistahermosa, which is the progenitor of most other fighting bulls in Spain. Comparison with nonendangered breeds suggests admixture of Alpine and/or Pyrenean mountain cattle in the ST, which may contribute to the high level of linkage disequilibrium in this population.

Martín-Burriel I ，Rodellar C ，Lenstra JA ，Sanz A ，Cons C ，Osta R ，Reta M ，De Argüello S ，Sanz A ，Zaragoza P ... -  《JOURNAL OF HEREDITY》

Relative breed contributions to neutral genetic diversity of a comprehensive representation of Iberian native cattle.

Cañón J ，García D ，Delgado JV ，Dunner S ，Telo da Gama L ，Landi V ，Martín-Burriel I ，Martínez A ，Penedo C ，Rodellar C ，Zaragoza P ，Ginja C ... -  《-》