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Search Results: 1 - 10 of 117860 matches for " T.; Gunski "
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Descripción cariotípica de Spheniscus magellanicus (Spheniscidae)
Ledesma,Mario A.; Freitas,T. R. O.; Da Silva,J.; Da Silva,Fernanda; Gunski,R. J.;
El hornero , 2003,
Abstract: the karyotype and the c-band pattern of spheniscus magellanicus are described here for the first time. peripheral blood samples from three females and four males were taken in imbé (rio grande do sul, brazil). long-time cultures of leukocytes were made in order to obtain mitotic metaphases. the diploid number was determined from the analysis of 30 metaphases. the karyotype of spheniscus magellanicus presents 68 chromosomes. pairs 1, 2, 4, 5 and 7 are submetacentric, pairs 6 and 10 are metacentric, pairs 3, 8 and 9 are telocentric, and the remaining ones are small telocentric chromosomes. the sex chromosomes z and w are submetacentric. the study carried out with c bands demonstrated that the w chromosome is totally heterocromatic, while the z chromosome does not present positive marks. centromeric marks can be observed in the macrochromosomes and in some microchromosomes. the only observed difference found among this species and the previously analyzed spheniscus demersus and spheniscus humboldti, resides in the diploid number 72 and 78 of those species, respectively. these differences are observed exclusively at the level of microchromosomes, indicating a high homogeneity in the diploid number and chromosome morphology of this group.
Estima??o de parametros genéticos entre pesos pré e pós-desmama na ra?a Nelore
Garnero,A.V.; Mu?oz,M.C.C.D.; Marcondes,C.R.; L?bo,R.B.; Lira,T.; Gunski,R.J.;
Archivos de Zootecnia , 2010, DOI: 10.4321/S0004-05922010000200019
Abstract: correlations among two or more traits indicate the extent to which they are associated. the level and magnitude of this association are key factors in genetic improvement because the goal is to enhance the genetic makeup of a group of traits that act simultaneously. therefore, the aim of this study was to estimate the components of variance and heritability for standard weights at 120, 240, 365, 450 and 550 days of age (p120, p240, p365, p450 and p550, respectively), and the genetic correlation among p120 and other weights in nellore cattle using a database of 29 769 records. bivariate analysis was carried out for all the traits using p120 as an anchor, and additive covariance was fixed as an analytical strategy in order to obtain genetic correlation estimates. heritability (h2) values were 0.21 for p240; 0.37 for p365; 0.36 for p450 and 0.42 for p550. the estimation of h2 varied between 0.23 and 0.31 for w120. genetic correlation estimates were high and positive, 0.96, 0.87, 0.79 and 0.76 among p120 and p240, p365, p450 and p550, respectively. these values indicate that selection for weight at younger ages will lead to a corresponding change in later weight, in the same direction.
Nucleolar organizer regions and a new chromosome number for Rhea americana (Aves: Rheiformes)
Gunski, Ricardo José;Giannoni, Miriam Luz;
Genetics and Molecular Biology , 1998, DOI: 10.1590/S1415-47571998000200006
Abstract: sequential banding analysis (giemsa-c-banding-ag nor) of chromosomes of the common rhea (rhea americana) was performed. metaphases were obtained by peripheral blood lymphocyte culture and monolayer embryo cell culture. the diploid chromosome number was 80, different from the 2n = 82 in previous reports. macrochromosome pairs 1, 2 and 5 were submetacentric and pair 3, subacrocentric. the 4th pair was acrocentric and all of the microchromosomes appeared to be acrocentric, with the exception of a clearly metacentric pair which was fully heterochromatic. the z was slightly larger than the w, both being acrocentric and c-band negative. nucleolar organizer regions were observed in the secondary constriction of a microchromosome pair. correct identification of the nor-bearing pair was possible only by sequential analyses, giemsa staining followed by the ag-nor technique.
Nucleolar organizer regions and a new chromosome number for Rhea americana (Aves: Rheiformes)
Gunski Ricardo José,Giannoni Miriam Luz
Genetics and Molecular Biology , 1998,
Abstract: Sequential banding analysis (Giemsa-C-banding-Ag NOR) of chromosomes of the common rhea (Rhea americana) was performed. Metaphases were obtained by peripheral blood lymphocyte culture and monolayer embryo cell culture. The diploid chromosome number was 80, different from the 2n = 82 in previous reports. Macrochromosome pairs 1, 2 and 5 were submetacentric and pair 3, subacrocentric. The 4th pair was acrocentric and all of the microchromosomes appeared to be acrocentric, with the exception of a clearly metacentric pair which was fully heterochromatic. The Z was slightly larger than the W, both being acrocentric and C-band negative. Nucleolar organizer regions were observed in the secondary constriction of a microchromosome pair. Correct identification of the NOR-bearing pair was possible only by sequential analyses, Giemsa staining followed by the Ag-NOR technique.
Plant Composition of Skuas Nests at Hennequin Point, King George Island, Antarctica  [PDF]
Margéli Pereira de Albuquerque, Filipe de Carvalho Victoria, Adriano Luís Schünemann, Jair Putzke, Ricardo José Gunski, Suzana Seibert, Maria Virginia Petry, Antonio Batista Pereira
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.35082
Abstract: We investigate the plant composition in the Skuas nest at Hennequin Point, located in the Admiralty Bay Area, King George Island, Antarctica. Sample of 61 activity nests were analyzed. 21 plant and lichenized fungi species were found in the nest composition, being the mosses Sanioniauncinata (Hedw.) Loeske and Polytrichastrumalpinum (Hedw) G. S. Smith the most frequent species found in the Skuas nests. Usneaantarctica Du Rietz was the most frequent lichen and the grass Deschampsiaantarctica Desv was the most frequent flowering plant found in the nests. These results contribute for the environmental menagement of the Admiralty Bay area research activities.
Análisis citogenético de Panthera Onca (Felidae: Pantetherinae) de la provincia de Misiones, Argentina
Ledesma,Mario A.; Ledesma,Cristian O.; Schiaffino,Karina; Rinas,Miguel A.; Gunski,Ricardo J.;
Mastozoolog?-a neotropical , 2004,
Abstract: the objective of the present work was to establish the chromosomal number and the patterns of g and nor of captive jaguar specimens from misiones province. cytogenetic analysis showed that diploid chromosome number of these specimens was 38, distributed in 6 autosomal groups (a, b, c, d, and, f) and the sex pair, showing a great similarity with the other species of this group previously analyzed in this family, when patterns of g bands as well as the location of the nor where compared.
Genetic trends in the expected progeny difference of the asymptotic weight of Nelore females
Garnero, Analía del Valle;Marcondes, Cintia Righetti;Gunski, Ricardo José;Oliveira, Henrique Nunes de;L?bo, Raysildo Barbosa;
Genetics and Molecular Biology , 2006, DOI: 10.1590/S1415-47572006000400012
Abstract: there are few studies on weight covering the full life cycle of zebu cattle, and there is no entire growth description or mean growth pattern for animals belonging to this breed. in order to provide such data, 1,158 nelore females born between 1985 and 1995 were weighed 14,563 times from birth to full growth maturity, in ten herds spread over seven brazilian states. the von bertalanffy, brody, logistic and gompertz non-linear models were used to obtain the asymptotic weights (a) and the maturation rates (k). the (co)variance and breeding value components for a and k were obtained by using the multiple trait derivative free restricted maximum likelihood method under the animal model. genetic trends were calculated in function of the mean expected progeny differences (epd) for the trait (a or k) divided by the number of animals according to their year of birth. the genetic trends of the expected progeny difference with reference to the date of birth of the cows were, on average, -6.5g y-1 for a and 2.0g y-1 for k, close to zero as confirmed by the low (0.0023 to 0.003) coefficient of regression values. the curve parameters are recommended as a selection criterion to reach precocity and avoid adult weight increase in the female herd.
Estimativas de parametros genéticos para características incluídas em critérios de sele o em gado Nelore
Gunski Ricardo José,Garnero Analía del Valle,Borjas Arcadio de los Reyes,Bezerra Luiz Ant?nio Framartino
Ciência Rural , 2001,
Abstract: Foram analisados registros de 20 rebanhos integrantes do Programa de Melhoramento Genético da Ra a Nelore (PMGRN), estudando-se as seguintes variáveis: ganho de peso por dia de idade até os 120, 200, 310 e 350kg (GPDpesok), peso padr o aos 120, 240, 365 e 550 dias de idade e peso real às idades mencionadas. As análises unicaráter mediante Modelo Animal, usando o aplicativo MTDFREML, proporcionaram estimativas de herdabilidades semelhantes para os pesos pré-desmama, variando entre 0,21-0,27 para o efeito direto, sendo que a correla o genética entre efeitos diretos e maternos foi negativa, variando entre -0,42 a -0,24. Para os pesos pós-desmama os coeficientes de herdabilidade foram maiores para as variáveis pesos padr o e peso real do que em rela o ao ganho de peso por dia de idade. A correla o genética mostrou a mesma tendência para os dois primeiros tipos de características e, para última, foi positiva e próxima de zero. A contribui o do efeito aditivo materno e do ambiente permanente para a variancia fenotípica na maioria das características estudadas justificam sua inclus o em programas de Melhoramento genético na ra a Nelore. Os resultados indicam que, para o período pós-desmama, a sele o por peso seria mais eficiente do que para o GPD.
Nucleolar organizer regions in Sittasomus griseicapillus and Lepidocolaptes angustirostris (Aves, Dendrocolaptidae): evidence of a chromosome inversion
Barbosa, Marcelo de Oliveira;Silva, Rubens Rodrigues da;Correia, Vanessa Carolina de Sena;Santos, Luana Pereira dos;Garnero, Analía del Valle;Gunski, Ricardo José;
Genetics and Molecular Biology , 2013, DOI: 10.1590/S1415-47572013000100010
Abstract: cytogenetic studies in birds are still scarce compared to other vertebrates. woodcreepers (dendrocolaptidae) are part of a highly specialized group within the suboscines of the new world. they are forest birds exclusive to the neotropical region and similar to woodpeckers, at a comparable evolutionary stage. this paper describes for the first time the karyotypes of the olivaceous and the narrow-billed woodcreeper using conventional staining with giemsa and silver nitrate staining of the nucleolar organizer regions (ag-nors). metaphases were obtained by fibular bone marrow culture. the chromosome number of the olivaceous woodcreeper was 2n = 82 and of the narrow-billed woodcreeper, 2n = 82. ag-nors in the largest macrochromosome pair and evidence of a chromosome inversion are described herein for the first time for this group.
Análise bayesiana do índice perímetro escrotal/peso de animais Nelore do Estado do Tocantins, Brasil
Marcondes,C.R.; Araújo,R.O.; Vozzi,P.A.; Gunski,R.J.; Garnero,A. del V.; L?bo,R.B.;
Archivos de Zootecnia , 2011,
Abstract: the aim of this study was to estimate the genetic parameters of the index scrotal circumference/weight standarized for 365 days of age (ind365), via bayesian inference, in two separate models of analysis on nellore animals born in the tocantins state, brazil. the file was composed of 693 records of the ind365 divided into 16 contemporaneous group. variance components were analyzed via bayesian inference, through the programs in fortran language. sampling of every 100 or 500 rounds and a little conservative burn-in can be implemented. means of direct heritabilities were 0.18 (with and without maternal effect) and 0.14 for maternal heritabilities. these results suggest that the ind365 can be used as alternative criterion in breeding programs to nellore cattle and respond satisfactorily to the selection process.
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