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Curraleiro Pé-Duro (CPD) cattle, a Brazilian local breed, are animals that are highly resistant to infectious and parasitic diseases. Strategies for the conservation of the breed and the genetic resistance to diseases should also consider the characteristics of the breed. The objective of this study was to analyze the diversity and population structure of the CPD breed using microsatellite markers and to correlate the serological profiles for causative agents of brucellosis, leptospirosis, neosporosis, leukosis, infectious bovine rhinotracheitis, and bovine viral diarrhea. DNA samples of 608 bovines were amplified and genotyped using 28 microsatellite markers for breed characterization. The genotypes were assigned to three clusters, indicating a substructure population related to the geographic distance. The observed heterozygosity was lower than that expected in most loci, and fixation index (Fst) in the subpopulation values ranged from 0.03073 (ETH3) to 0.402 (INRA63) on cluster 1, from 0.00 (INRA32) to 0.39359 (INRA63) on cluster 2, and from 0.00 (INRA32) to 0.28483 (TGLA53) on cluster 3. The Brucella spp., Neospora caninum, and Bovine Leukemia Virus frequencies were significantly different (p < 0.05) between clusters. The differences between the occurrences of diseases were not sufficient to indicate a genetic subpopulation with increased resistance to infections.
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American Criollo pigs are thought to descend mainly from those imported from the Iberian Peninsula starting in the late 15th century. Criollo pigs subsequently expanded throughout the Americas, adapting to very diverse environments, and possibly receiving influences from other origins. With the intensification of agriculture in the mid-20th century, cosmopolitan breeds largely replaced Criollo pigs, and the few remaining are mostly maintained by rural communities in marginal areas where they still play an important socio-economic and cultural role. In this study, we used 24 microsatellite markers in samples from 1715 pigs representing 46 breeds with worldwide distribution, including 17 American Criollo breeds, with the major focus of investigating their genetic diversity, structure and breed relationships. We also included representatives of the Iberian, Local British, Hungarian, Chinese and Commercial breeds, as well as Wild Boar, in order to investigate their possible influence in the genetic composition of Criollos. Our results show that, when compared with the other breeds, Criollo pigs present higher levels of genetic diversity, both in terms of allelic diversity and expected heterozygosity. The various analyses indicate that breed differentiation overall explains nearly 21% of the total genetic diversity. Criollo breeds showed their own identity and shared a common genetic background, tending to cluster together in various analyses, even though they differ from each other. A close relationship of Criollos with Iberian breeds was revealed by all the different analyses, and the contribution of Iberian breeds, particularly of the Celtic breeds, is still present in various Criollo breeds. No influence of Chinese breeds was detected on Criollos, but a few were influenced by Commercial breeds or by wild pigs. Our results confirm the uniqueness of American Criollo pigs and the role that Iberian breeds have played in their development.
Assuntos
Variação Genética/genética , Repetições de Microssatélites/genética , Filogenia , Suínos/genética , Alelos , América , Animais , Europa (Continente) , Patrimônio Genético , Genótipo , HumanosRESUMO
Creole sheep in México have undergone crossbreeding, provoking the loss of genetic variability. The objective of the present study is to determine the intra-racial genetic diversity, the genetic relationship with other genotypes, and the populational substructure of the Oaxacan Creole sheep. Twenty-nine blood samples were obtained of Creole sheep of the Oaxaca Mixteca region in México. A genetic analysis was made with 41 microsatellites recommended for studies of genetic diversity in sheep. An analysis was made of genetic diversity, populational structure, and genetic distance with 27 other sheep populations. The study found 205 alleles with a range of 2 to 9 by locus and an effective number of 3.33. The intra-racial analysis showed a moderate genetic diversity with values of expected heterozygosity of 0.686 and observed of 0.756, a mean polymorphic information content of 0.609, and a mean coefficient of consanguinity of -0.002. In interracial genetic diversity for the coefficients of consanguinity, the values were FIS = 0.0774, FIT = 0.16993, and FST = 0.10028, showing an elevated genetic distance with other creole breeds, but close to Argentine Creole, to another Creole of México and the Spanish Merino. Its genetic structure showed that it does not have any populational subdivision nor mixes with the others analyzed. It is concluded that it is a distinct and isolated population and is proposed as the creole breed "Chocholteca" for its conservation.
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In this study, we aimed to evaluate the genetic diversity within and among chicken breeds from the northeast region of Brazil (states of Bahia and Piauí) using microsatellite markers. In addition, we assessed the identity and genetic relationships of chickens from Europe, Africa, and South America, as well as their influence on the formation of the Brazilian breeds. A total of 25 microsatellite markers and a panel containing 886 samples from 20 breeds (including the Brazilian chickens) were used in this study. Different statistical parameters were used to estimate the genetic diversity and relationship among the genetic groups studied. Our study indicates that the Brazilian Creole chickens have high genetic variability. The results show that chickens reared in the states of Bahia and Piauí could have originated from different ancestors. The Brazilian breeds studied have an evolutionary relationship with chickens from Portugal, Nigeria, Chile, and Spain. Our results will contribute directly to the conservation and recognition of Brazilian Creole chicken breeds and provide a solid basis for the demonstration of their genetic identity and genetic conservation of American Creole chicken populations.
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The genetic diversity of six Brazilian native goats was reported using molecular markers. Hair samples of 332 animals were collected from different goat breeds (Moxotó, Canindé, Serrana Azul, Marota, Repartida, and Graúna) from five states of Northeast Brazil (Paraíba, Pernambuco, Rio Grande do Norte, Bahia, and Piauí). A panel of 27 microsatellites or single sequence repeats (SSRs) were selected and amplified using a polymerase chain reaction (PCR) technique. All populations showed an average allele number of over six. The mean observed heterozygosity for Brazilian breeds was superior to 0.50. These results demonstrated the high genetic diversity in the studied populations with values ranging from 0.53 (Serrana Azul) to 0.62 (Repartida). The expected average heterozygosity followed the same trend ranging from 0.58 (Serrana Azul) to 0.65 (Repartida), and the values obtained are very similar for all six breeds. The fixation index (Fis) had values under 10% except for the Moxotó breed (13%). The mean expected heterozygosity of all Brazilian populations was over 0.50. Results indicated a within-breed genetic variability in the Brazilian breeds based on the average number of alleles and the average observed heterozygosity. The interbreed genetic diversity values showed proper genetic differentiation among local Brazilian goat breeds.
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The aim of the present paper was to evaluate genetic diversity within and among Ecuadorian bovine breeds using microsatellite markers. The genetic identity and the exotic influences from taurine or zebuine cosmopolitan breeds on Macabea, Loja, Santa Elena, Manabí and Isla de Puná breeds were evaluated. Twenty-eight microsatellite markers were tested across 254 individuals belonging to the five Ecuadorian populations to investigate intra and inter population genetic diversity levels. Nineteen markers in common with a set of 1595 samples of 35 previously typed breeds were used to determine the potential origin of Ecuadorian bovine breeds and to identify and quantify their genetic relationships. The findings of FIS > FST (0.0814 > 0.0499), even in the context of low but significant FST values, may be indicative of the intrapopulation origin of the variability of allelic frequencies across populations. Conclusively, the study of genetic distances and population structure suggested the origin of Ecuadorian populations may likely stem from Southern Spanish breeds, with no significant recent influence from cosmopolitan Taurine or Zebuine breeds. These findings may provide a solid basis for the demonstration of an Ecuadorian breeds identity in the framework of the genetic conservation of the American creole populations.
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Bovinos/genética , Variação Genética , Repetições de Microssatélites , Animais , Equador , Frequência do Gene , FilogeniaRESUMO
The largest population of goats (62%) in Ecuador is in the dry forest region in the south of the country. A Creole goat, named "Chusca Lojana", has adapted to the dry forest region where environmental conditions are warm-dry, with sparse vegetation. Knowledge of the genetic information of the Creole goat is important to determine intra-racial diversity, the degree of genetic distance among other breeds of goats, and the possible substructure of the population, which is valuable for the conservation of such a species' genetic resources. A total of 145 samples of the Creole goat was taken from the four biotypes previously identified. Genetic analyses were performed using 38 microsatellites recommended for studies of goat genetic diversity (FAO-ISAG). The results of within-breed genetic diversity showed a mean number of alleles per locus (MNA) of 8, an effective number of alleles (Ae) of 4.3, an expected heterozygosity (He) of 0.71, an observed heterozygosity (Ho) of 0.63, polymorphic information content (PIC) of 0.67, and an FIS value of 0.11. Between-breed genetic diversity among 43 goat populations (native of Spain, American Creole, Europeans, and Africans) showed the following values: FIS = 0.087, FIT = 0.176, and FST = 0.098. Regarding the analysis of the population structure, the results showed that the Creole Chusca Lojana goat population is homogeneous and no genetic separation was observed between the different biotypes (FST = 0.0073). In conclusion, the Chusca Lojana goat has a high genetic diversity, without exhibiting a genetic substructure. Therefore, it should be considered as a distinct population because crossbreeding with other breeds was not detected.
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Latin American Creole chickens are generally not characterized; this is the case in Ecuador, where the lack of scientific information is contributing to their extinction. Here, we developed a characterization of the genetic resources of Ecuadorian chickens located in three continental agroecosystems (Pacific coastal, Andean, and Amazonian). Blood samples of 234 unrelated animals were collected in six provinces across Ecuador: Bolívar, Chimborazo, Cotopaxi, Guayas, Morona Santiago, and Tungurahua, in order to perform a genetic characterization and population structure assessment using the AVIANDIV project microsatellites panel (30 loci) and D-loop sequences of mitochondrial DNA and comparing with reference data from other breeds or genetic lines. The results indicate that Ecuadorian Creole chickens are the result of the admixture of different genetic groups that occurred during the last five centuries. While the influence of South Spanish breeds is demonstrated in the colonial age, genetic relationships with other breeds (Leghorn, Spanish fighter cock) cannot be discarded. The geographical configuration of the country and extreme climate variability have influenced the genetic isolation of groups constituting a homogeneous genetic status into the whole population. This is not only a source of genetic variation, but also a critical point because genetic drift produces a loss of genetic variants.
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Macabea cattle are the only Bos taurus breed that have adapted to the wet tropical conditions of the Amazon. This breed has integrated into the culture of the indigenous Shuar-Asuar nations probably since its origins, being one of the few European zoogenetic resources assimilated by the deep-jungle Amazon communities. Despite its potential for local endogenous sustainable development, this breed is currently endangered. The present study used molecular genetics tools to investigate the within- and between-breeds diversity, in order to characterize the breed population, define its associations with other breeds, and infer its origin and evolution. The within-breed genetic diversity showed high values, as indicated by all genetic parameters, such as the mean number of alleles (MNA = 7.25±2.03), the observed heterozygosity (Ho = 0.72±0.02) and the expected heterozygosity (He = 0.72±0.02). The between-breeds diversity analysis, which included factorial correspondence analysis, Reynolds genetic distance, neighbor-joining analysis, and genetic structure analysis, showed that the Macabea breed belongs to the group of the American Creoles, with a Southern-Spain origin. Our outcomes demonstrated that the Macabea breed has a high level of purity and null influences of exotic cosmopolitan breeds with European or Asiatic origin. This breed is an important zoogenetic resource of Ecuador, with relevant and unique attributes; therefore, there is an urgent need to develop conservation strategies for the Macabea breed.
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Bovinos/genética , Animais , Biodiversidade , Feminino , Masculino , Repetições de Microssatélites/genética , América do SulRESUMO
The Uruguayan Creole cattle genetic reserve consists of a herd of about 600 animals (bulls, cows and calves) located in an indigenous habitat of 650 hectares. In a previous study, a random sample from this herd showed high heterozygosity and a Hardy-Weinberg equilibrium for markers of major genes related to milk production. To study its genetic diversity we genotyped a sample of bulls (N = 19 out of 23 for the whole herd) using the PCR reaction with a set of 17 microsatellite markers. Between two and seven different alleles were identified per microsatellite in a total of 73 alleles. The expected mean heterozygosity (He) per locus was between 0.465 and 0.801, except for microsatellite HEL13 which gave a He value of 0.288. The expected mean heterozygosity was 0.623 and the polymorphic information content (PIC) was between 0.266 for HEL13 and 0.794 for CSSM66. The genetic diversity found in polymorphic markers in the breeding bulls of this Creole cattle population supports previous genetic analyses using major production genes and indicate that further studies should be carried out on this population to provide data of interest to cattle production.