Nataliê Silva

Polimorfismo genético da leptina e do receptor do hormônio do crescimento em caprinos

EnglishThis study aimed to evaluate the relationship between leptin gene polymorphism (LEP), specifically exon 2, and microsatellite of the growth hormone receptor (GHR-SSR) with the growth characteristics of Anglo-Nubian and Boer goats to identify useful markers for selecting animals with high genetic merit. The Toolkit program was used for obtaining the allele frequencies and heterozy- gosity. Hardy-Weinberg equilibrium test was performed with GENEPOP software. Markers were in desequilibrium in all populations studied. Observed heterozygosity values for LEP were greater than expected heterozygosity. All animals showed the same electrophoretic pattern with two alleles (150 and 152 bp). On GHR locus was detected five alleles ranging from 90 to 125 bp. Birth weight (BW) and weaning weight (PD) were used to evaluate the influence of polymorphic fragments on the animal growth. They were analyzed by GLM procedure of SAS software. The genotypes showed a significant effect on birth (BW) and weaning weight (PD). It is necessary to increase the number of samples to confirm the relationship among GHR and leptina polymorphic fragments GHR and growth characteristics. portuguesObjetivou-se estudar a relacao entre o polimorfismo no gene da leptina (LEP), especi- ficamente o exon 2, e o microssatelite do receptor do hormonio do crescimento (SSR-GHR) com as caracteristicas de crescimento em animais das racas Anglo-Nubiana e Boer, a fim de identificar marcadores que possam ser uteis na selecao desses animais da especie caprina de elevado merito genetico. Foram obtidas as frequencias alelicas e heterozigosidade com auxilio do progra- ma Toolkit. O teste para o equilibrio de Hardy- Weinberg foi feito com auxilio do GENEPOP, no qual os marcadores se mostraram em desequilibrio para as populacoes. Para a LEP os valores de heterozigosidade observada foram bem maiores do que os esperados e todos os animais apresentaram o mesmo padrao eletroforetrico com dois alelos (150 e 152 pb). No loco do GHR observou-se cinco alelos com tamanho variando de 90 a 125 pb. Para verificar a influencia dos genotipos dos fragmentos polimorficos do GHR e da leptina sobre o desenvolvimento dos animais foram utilizados os pesos ao nascer (PN) e ao desmame (PD), para os quais foi feito analise de variância e teste de medias com auxilio do procedimento GLM do programa SAS. Observou- se efeito significativo dos genotipos sobre os pesos ao nascer (PN) e a desmame (PD). Sugere- se, o estudo destes polimorfismos em maior nume- ro de animais para confirmacao do efeito sobre caracteristicas de crescimento.

Polymorphism of mitochondrial DNA in the Brazilian Canindé goat breed

The success of the geographical distribution of goat populations around the world is a consequence of the adaptive potential of these breeds. Several relevant traits to the success of the species in colonizing different ecosystems (and use by man) evolved before domestication. These features were relevant for the selection of different breeds. Each breed represents a genetic heritage that may be unique and essential for maintaining the species. The objective of this study was to catalog the mtDNA haplotypes of the Brazilian autochthonous Canindé goat breed and to characterize the genetic diversity observed in subpopulations by sequencing a 481-bp fragment corresponding to the first portion of the control region in 178 individuals from 10 herds, sampled in six Brazilian states. The global population displays a total of 29 haplotypes and 56 polymorphic sites. About one-third (10) of the haplotypes were common to all subpopulations while the remaining (19) were exclusive to a single subpopulation. The population exhibited high average haplotype diversity (0.82), with maximum and minimum values of 0.90 and 0.56 in individual subpopulations, respectively. In contrast, nucleotide diversity was 0.014, with maximum and minimum values of 0.020 and 0.004, respectively. The spatial analysis of molecular variance did not detect structure within the Canindé goat breed, and analysis of molecular variance revealed that 88.4% of the variation observed in the population was due to differences among individuals in the same subpopulation. Only 11.4% of the genetic variation referred to differences among subpopulations. About one-third (33.1%) of the individuals within population shared the same haplotype, which may be due not only to the breed developing from a small number of matrilines. The Brazilian autochthonous Canindé breed was classified as haplogroup A, a haplotype predominant in the Europe region.