Navegando por Autor "HAMOY, Igor Guerreiro"

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Acesso aberto (Open Access)
High genetic diversity and connectivity in Colossoma macropomum in the Amazon basin revealed by microsatellite markers
(Universidade Federal do Pará, 2017-03) GOMES, Paola Fabiana Fazzi; GUERREIRO, Sávio Lucas de Matos; PALHETA, Glauber David Almeida; MELO, Nuno Filipe Alves Correa de; SANTOS, Sidney Emanuel Batista dos; HAMOY, Igor Guerreiro
Colossoma macropomum is the second largest scaled fish of the Amazon. It is economically important for commercial fisheries and for aquaculture, but few studies have examined the diversity and genetic structure of natural populations of this species. The aim of this study was to investigate the levels of genetic variability and connectivity that exist between three natural populations of C. macropomum from the Amazon basin. In total, 247 samples were collected from the municipalities of Tefé, Manaus, and Santarém. The populations were genotyped using a panel of 12 multiplex microsatellite markers. The genetic diversity found in these populations was high and similar to other populations described in the literature. These populations showed a pattern of high gene flow associated with the lack of a genetic structure pattern, indicating that the number of migrants per generation and recent migration rates are high. The values of the FST, RST, and exact test of differentiation were not significant for pairwise comparisons between populations. The Bayesian population clustering analysis indicated a single population. Thus, the data provide evidence for high genetic diversity and high gene flow among C. macropomum populations in the investigated region of the Amazon basin. This information is important for programs aiming at the conservation of natural populations.
Acesso aberto (Open Access)
Myxobolus marajoensis sp. n. (Myxosporea: Myxobolidae), parasite of the freshwater catfish Rhamdia quelen from the Brazilian Amazon region
(Universidade Federal do Pará, 2017-12) ABRUNHOSA, Jacqueline Pompeu; SINDEAUX NETO, José Ledamir; SANTOS, Andrea Kely Campos Ribeiro dos; HAMOY, Igor Guerreiro; MATOS, Edilson Rodrigues
This study provides morphological and molecular data of a new parasite species found in the muscle layer of the intestinal tract of the South American silver catfish, Rhamdia quelen from Marajó Island region (Pará State, Brazil), an important fishery resource with recognized potential for fish farming. The morphology of these parasites was reanalyzed and phylogenetic analyses were run on their 18S rDNA gene sequences. The spores were morphologically distinct from those of other Myxobolus species described previously. The obtained partial sequence of the 18S rDNA gene sequences of the new species were compared to those of 24 other Myxobolus and Henneguya species available in GenBank. The results of morphological and molecular analyses indicated clearly the existence of a new species, Myxobolus marajoensis sp. n.
Acesso aberto (Open Access)
Prevalence of hereditary risk factors for thrombophilia in Belém, Brazilian Amazon
(2006) YOSHIOKA, France Keiko Nascimento; ARAÚJO, Amélia Goes de; TAVELLA, Marli H.; HAMOY, Igor Guerreiro; GUERREIRO, João Farias
Different risk factors for venous thromboembolism (VTE) have been identified, including hereditary abnormalities in the mechanisms of coagulation and fibrinolysis. We investigated five genetic polymorphisms (FVL G1691A, FII G20210A, MTHFR C677T, TAFI A152G and TAFI T1053C) associated with VTE in individuals from the city of Belém in the Brazilian Amazon who had no history of VTE. No significant difference was found between the observed and expected genotype frequencies for the loci analyzed. We found high frequencies of MTHFR C677T (33.9%) and TAFI T1053C (74%) and low frequencies of FVL (1.6%), FII G20210A (0.8%) and TAFI A152G (0.8%). The FVL G1691A, FII G20210A and MTHFR C677T frequencies were similar to those for European populations and populations of European descent living in the city of Ribeirão Preto in the Brazilian state of São Paulo. The frequency of the two TAFI mutations in the Belém individuals was not significantly different from that described for individuals from Ribeirão Preto. We suggest that the risks for VTE in the population of Belém are of the same magnitude as that observed in European populations and in populations with an expressive European contribution.