Diversidade genética em caprino Marota e manejo genético para rebanhos de conservação

Abstract

¹Universidade Federal do Piauí. Brasil. ²Universidade Estadual de São Paulo. Brasil. ³Embrapa Meio Norte. Brasil. Palavras chave adicionais Microarranjos. Recursos genéticos. Risco de extinção. SNP.resUMo Objetivou-se avaliar a diversidade genética em rebanhos de caprinos Marota e verificar o impacto do uso de marcadores moleculares no manejo genético em rebanho de conservação. Utilizando-se Chip SNP caprino 50K genotipou-se 76 animais do rebanho de conservação institucional e 10 animais de um rebanho particular. Avaliou-se a dispersão dos animais por Análise de Componentes Principais (PCA) e em dendograma. Simulou-se acasalamentos entre animais que apresentaram maior distância no dendograma e menor coeficiente de consanguinidade (FIS) (Manejo I) para verificar a eficiência desse manejo, em relação à ocorrência de acasalamentos ao acaso (Manejo II). Valores altos de heterozigosidade observada (Ho) e esperada (He) nos animais adultos (Ho=0,372±0,005 e He=0,405±0,007) e nas crias (Ho=0,359±0,012 e He=0,374 ±0,028) e média do FIS igual a 6,4% indicam baixo risco de perda de genes no rebanho institucional. O rebanho particular também apresentou variabilidade genética (Ho=0,374 e He=0,498), porém com maior risco em relação à endogamia (FIS= 22,7%). A PCA indicou semelhança genética entre os rebanhos. A simulação de 10 pares de acasalamentos de cada reprodutor indicou que a média do coeficiente de consanguinidade dos casais formados de acordo com o Manejo I, foi estatisticamente inferior à média dos pares acasalantes formados de acordo com o Manejo II. Concluiu-se que existe variabilidade genética nos rebanhos analisados, porém com indício de consanguinidade; e que em rebanhos pequenos nos quais a reposição é feita com animais do próprio rebanho, a definição de acasalamentos com base em critérios genéticos, é opção para controle de consanguinidade.inforMation Cronología del artículo. Recibido/sUMMarYThis study was aimed at assessing the genetic diversity in herds of Marota goats and examine the impact of molecular markers in the genetic management of conservation herds. Seventy-six animals of one conservation heard and ten animals of a private herd were genotyped with the Illumina 50K goat SNP Chip. The dispersion of animal was evaluated with a principal component analysis (PCA) and a dendogram. Matings were simulated between animals with the largest distance in the dendogram and lowest coefficient of inbreeding (FIS) (Management I) and compared to random mating (Management II). High values of observed (Ho) and expected (He) heterozygosity were obtained for adult animals (Ho=0.372 and He=0.405) and offspring (Ho=0.359 and He=0.374). The mean FIS was 6.4%, indicating a low risk of gene loss in the conservation herd. Genetic variability was also observed in the private herd (Ho=0.374 and He=0.498), but the risk of endogamy was higher. The PCA revealed that the two herds were genetically similar. The simulation of 10 mating pairs of each breeder indicated that the mean coefficient of inbreeding of the formed pairs in Mana...

Capra hircus outliers markers in Brazil: Searching for genomic regions under the action of natural selection

“…The results showed that all paired FST values between populations were statistically significant (p<0.01). In our study, high genetic differentiation (FST=0.16) was observed between the Marota gene group and the Anglo-Nubian breed, indicating that Marota has considerable genetic diversity, suggesting that natural selection may have been a key factor in shaping the genetic diversity detected in this breed ( Oliveira Moura et al, 2019 a).…”

“…At first, genetic structuring analyses based on the main components revealed that the cluster number that explains the genomic variation data more clearly, between the Marota genetic group and the Anglo-Nubian breed, was K = 2 for analysis of SNPs markers. In this sense, when the subpopulations are represented in the Cartesian plane, constituted by the first two main components, there was a clear separation between the groups of animals ( Figure2 ), with an individual from the distinct groups closely related genetically, which indicates that there is a mixed between breeds ( Oliveira Moura et al, 2019 a)…”

“…The genetic diversity was higher between breeds than within individuals of standardized breeds, as expected in local breeds diversity ( Grasso et al, 2014 ). Global F ST of 0.16 shows the important genetic differentiation between Anglo-Nubian (an important standardized breed introduced in the 1950s in Brazil) and Marota (local goat population, no-directional selected), despite the years of coexistence in this region and the extensive breeding system in which the herds mate ( Oliveira Moura et al, 2019 a).…”

“…The present study, identified signatures of selection on the chromosome 06 gene region corroborates the information contained in another study ( Brito et al ., 2017 ). Particularly, the genome markers present in Marota local breed provide an opportunity to determine adaptive characteristics, correlated to the way of life of the goat animal in the semi-arid tropical regions of Brazil ( Oliveira Moura et al, 2019 a, b).…”

Genomic analysis revealed hotspots of genetic adaptation and risk of disappearance in the Brazilian goat populations

“…Among livestock species, goats (Capra hircus) play a crucial role in economic development, significantly contributing to large-scale production, particularly of milk, and supporting rural subsistence by enhancing income for families in developing countries [1,2]. In the Brazilian context, farming activities involving small ruminants are divided between large producers and small breeders, with goats prominently adapted to the semi-arid tropics [3,4]. Goat landraces are generally more genetically diverse than commercial breeds, as they have been developed through a long history of breeding by processes markedly different from those used for commercial breeds.…”