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Heterose e distâncias genéticas moleculares para a produção de grãos em soja; Heterosis and molecular genetic distances for grain yield in soybeans

COLOMBARI FILHO, José Manoel; GERALDI, Isaias Olívio; BARONA, Marco Antonio Acevedo
Fonte: Editora da Universidade Federal de Lavras Publicador: Editora da Universidade Federal de Lavras
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
55.94%
Em soja, tem sido relatada a ocorrência de heterose para a produção de grãos, e embora a utilização de cultivares híbridas não seja ainda uma realidade nesta espécie, o conhecimento da heterose é importante para uma pré-seleção de cruzamentos, visto que cruzamentos mais heteróticos estão associados a uma maior divergência entre os genitores. Entretanto, a obtenção de sementes F1 em quantidade suficiente para a avaliação experimental em parcelas é muito difícil e, assim, outros indicadores da ocorrência da heterose poderiam ser muito úteis. Objetivou-se, neste trabalho a avaliação da heterose para a produção de grãos em soja e as suas relações com as distâncias genéticas (DG), obtidas com o marcador molecular AFLP. Seis híbridos F1 oriundos de cruzamentos com diferentes distâncias genéticas (DG) e os respectivos genitores foram avaliados em experimentos com quatro repetições, empregando o delineamento em blocos ao acaso. Foi observada uma grande variação entre os cruzamentos quanto às heteroses, isso é, de 6,29 a 56,50% em relação à média dos genitores ( h mg) e de -0,34 a 51,30% em relação ao genitor superior (h gs). As correlações entre as distâncias genéticas (DG) e as heteroses foram elevadas (r = 0...

Genetic diversity in Egeria densa and E. najas in Jupia Reservoir, Brazil

Mori, Edson S.; Martins, Dagoberto; Velini, Edivaldo Domingues; Marino, Celso L.; Gouvea, Cantidio F.; Leite, Suzi M. M.; Camacho, Edwin; Guries, Raymond P.
Fonte: Pontificia Univ Catolica Chile, Fac Agronomia Ingenieria Forestal Publicador: Pontificia Univ Catolica Chile, Fac Agronomia Ingenieria Forestal
Tipo: Artigo de Revista Científica Formato: 321-330
ENG
Relevância na Pesquisa
55.98%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); E.S. Mori, D. Martins, E.D. Velini, C.L. Marino, C.F. Gouvea, S.M.M. Leite, E. Camacho Palomino, and R.P. Curies. 2012. Genetic diversity in Egeria densa and E. najas in Jupia Reservoir, Brazil. Cien. Inv. Agr. 39(2):321-330. The aquatic plant species Egeria densa (Planch.) Casp and E. najas Planchon occur naturally in the Parana River Basin of southeastern Brazil. Hydroelectric dam construction in the river basin has created several lakes, changing the ecology of the river and altering the population ecology of Egeria. Large, dense populations of Egeria now grow in Jupia Lake and its tributaries, occasionally blocking hydroelectric turbines. This study is part of a larger project examining environmental changes associated with large dam projects; the research objective of this study was to assess patterns of genetic diversity in Egeria populations growing in Jupia and Tres Irmaos Lakes and their Parana River tributaries using genetic markers. Forty-two plants of E. najas and 46 of E. densa (for a total of 88 samples) were collected from 13 sites. Genotypes were identified by isoenzymes and Random Amplification of Polymorphic DNA RAPD markers. Using a genetic distance dendrogram we grouped all E. densa plants into one set and all E. najas plants into another set. The plant sample 8a...

Structure and genetic relationships between Brazilian naturalized and exotic purebred goat domestic goat (Capra hircus) breeds based on microsatellites

Oliveira, Joelliton Domingos de; Igarashi, Maria Luiza Silveira de Paiva; Machado, Théa Mírian Medeiros; Miretti, Marcos Mateo; Ferro, Jesus Aparecido; Contel, Eucleia Primo Betioli
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: 356-363
ENG
Relevância na Pesquisa
56%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); The genetic relationships and structure of fourteen goat (Capra hircus) populations were estimated based on genotyping data from 14 goat populations (n = 410 goats) at 13 microsatellite loci. We used analysis of molecular variance (AMOVA), principal component analysis (PCA) and F statistics (F IS, F IT and F ST) to evaluate the genetic diversity (Ho, He and ad) of the goats. Genetic distances between the 14 goat populations were calculated from allelic frequency data for the 13 microsatellite markers. Moderate differentiation was observed for the populations of the undefined breeds (including the Anglo-Nubian-M breed), the naturalized Brazilian breeds (Moxotó, Canindé), the exotic purebred breeds (Alpine, Saanen, Toggenbourg and Anglo-Nubian) and the naturalized Brazilian Graúna group. Our AMOVA showed that a major portion (88.51%) of the total genetic variation resulted from differences between individual goats within populations, while between-populations variation accounted for the remaining 11.49% of genetic variation. We used a Reynolds genetic distance matrix and PCA to produce a phenogram based on the 14 goat populations and found three clusters, or groups...

Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam

Hoffmann, Erika H.E.; Ribolla, Paulo E.M.; Ferreira, Marcelo U.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1-8
ENG
Relevância na Pesquisa
56%
Background: Despite the extensive polymorphism at the merozoite surface protein-1 (MSP-1) locus of Plasmodium falciparum, that encodes a major repetitive malaria vaccine candidate antigen, identical and nearly identical alleles frequently occur in sympatric parasites. Here we used microsatellite haplotyping to estimate the genetic distance between isolates carrying identical and nearly identical MSP-1 alleles. Methods: We analyzed 28 isolates from hypoendemic areas in north-western Brazil, collected between 1985 and 1998, and 23 isolates obtained in mesoendemic southern Vietnam in 1996. MSP-1 alleles were characterized by combining PCR typing with allele-specific primers and partial DNA sequencing. The following single-copy microsatellite markers were typed: Polyα, TA42 (only for Brazilian samples), TA81, TA1, TA87, TA109 (only for Brazilian samples), 2490, ARAII, PfG377, PfPK2, and TA60. Results: The low pair-wise average genetic distance between microsatellite haplotypes of isolates sharing identical MSP-1 alleles indicates that epidemic propagation of discrete parasite clones originated most identical MSP-1 alleles in parasite populations from Brazil and Vietnam. At least one epidemic clone propagating in Brazil remained relatively unchanged over more than one decade. Moreover...

Habitat continuity and geographic distance predict population genetic differentiation in giant kelp

Filipe, A.; Raimondi, P. T.; Reed, D. C.; Coelho, N. C.; Raphael, L.; Allison, W.; Serrão, Ester
Fonte: Ecological Society of America Publicador: Ecological Society of America
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
46.18%
Isolation by distance (IBD) models are widely used to predict levels of genetic connectivity as a function of Euclidean distance, and although recent studies have used GIS-landscape ecological approaches to improve the predictability of spatial genetic structure, few if any have addressed the effect of habitat continuity on gene flow. Landscape effects on genetic connectivity are even less understood in marine populations, where habitat mapping is particularly challenging. In this study, we model spatial genetic structure of a habitat-structuring species, the giant kelp Macrocystis pyrifera, using highly variable microsatellite markers. GIS mapping was used to characterize habitat continuity and distance between sampling sites along the mainland coast of the Santa Barbara Channel, and their roles as predictors of genetic differentiation were evaluated. Mean dispersal distance (σ) and effective population size (Ne) were estimated by comparing our IBD slope with those from simulations incorporating habitat continuity and spore dispersal characteristics of the study area. We found an allelic richness of 7–50 alleles/locus, which to our knowledge is the highest reported for macroalgae. The best regression model relating genetic distance to habitat variables included both geographic distance and habitat continuity...

Genetic distance between broodstocks of the marine shrimp Litopenaeus vannamei (Decapoda, Penaeidae) by mtDNA analyses

Francisco,Ana Karina de; Galetti Junior,Pedro Manoel
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2005 EN
Relevância na Pesquisa
56.08%
In the constantly growing Brazilian shrimp industry the evaluation of genetic relationships between broodstocks is an useful tool for shrimp culture management programs. We established the genetic relationships between five broodstocks of the white marine shrimp Litopenaeus vannamei (Penaeidae) based on the sequencing of the mtDNA 16S rRNA and cytochrome oxidase I (COI) regions. Although no divergence was found between the broodstocks for the highly conservative 16S rRNA gene, we did find an 8.2% distance between L. vannamei and the Farfantepenaeus subtilis. Analyses of the COI region showed genetic distances of only 0.2 to 1% between the broodstocks, which contrasted with the 10.9% mean distance found between L. vannamei and F. subtilis. The small genetic distance values obtained may be related to genetic drift or a founder effect that occurred during broodstocks establishment. The mtDNA analysis was able to characterize the genetic divergence between the broodstocks studied and could be helpful for defining better management strategies of these crustacea.

Structure and genetic relationships between Brazilian naturalized and exotic purebred goat domestic goat (Capra hircus) breeds based on microsatellites

Oliveira,Joelliton Domingos de; Igarashi,Maria Luiza Silveira de Paiva; Machado,Théa Mírian Medeiros; Miretti,Marcos Mateo; Ferro,Jesus Aparecido; Contel,Eucleia Primo Betioli
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2007 EN
Relevância na Pesquisa
56%
The genetic relationships and structure of fourteen goat (Capra hircus) populations were estimated based on genotyping data from 14 goat populations (n = 410 goats) at 13 microsatellite loci. We used analysis of molecular variance (AMOVA), principal component analysis (PCA) and F statistics (F IS, F IT and F ST) to evaluate the genetic diversity (Ho, He and ad) of the goats. Genetic distances between the 14 goat populations were calculated from allelic frequency data for the 13 microsatellite markers. Moderate differentiation was observed for the populations of the undefined breeds (including the Anglo-Nubian-M breed), the naturalized Brazilian breeds (Moxotó, Canindé), the exotic purebred breeds (Alpine, Saanen, Toggenbourg and Anglo-Nubian) and the naturalized Brazilian Graúna group. Our AMOVA showed that a major portion (88.51%) of the total genetic variation resulted from differences between individual goats within populations, while between-populations variation accounted for the remaining 11.49% of genetic variation. We used a Reynolds genetic distance matrix and PCA to produce a phenogram based on the 14 goat populations and found three clusters, or groups, consisting of the goats belonging to the undefined breed, the naturalized breeds and the exotic purebred breeds. The closer proximity of the Canindé breed from the Brazilian state of Paraíba to the Graúna breed from the same state than to the genetically conserved Canindé breed from the Brazilian state of Ceará...

Genetic distance and its association with heterosis in cacao

Dias,Luiz Antônio dos Santos; Marita,Jane; Cruz,Cosme Damião; Barros,Everaldo Gonçalves de; Salomão,Tânia Maria Fernandes
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2003 EN
Relevância na Pesquisa
56.06%
The efficiency of cacao breeding program can be increased by choosing superior crosses to be made between divergent clones. We assessed the genetic distance among five clones with RAPD data (genetic distance - GD) and with yield component data (Mahalanobis distance - MD). The clones were evaluated in a diallel, during five years, for five yield components. A total of 130 RAPD bands were scored. GD and MD were used to determine the correlation between genetic distances among clones and the performance of their hybrids. The correlation between GD and MD was 0.67 (P=0.03). Both distances were related to heterotic performance of hybrids for wet seed weight/plant and wet seed weight/fruit. The average hybrid performance for the same two yield components was correlated with only MD. Hence, genetic distances measured by RAPD and yield components can be used as a guide to the choice of the superior crosses.

Relationship between Spatial and Genetic Distance in Agrobacterium spp. in 1 Cubic Centimeter of Soil

Vogel, J.; Normand, P.; Thioulouse, J.; Nesme, X.; Grundmann, G. L.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /03/2003 EN
Relevância na Pesquisa
46.1%
The spatial and genetic unit of bacterial population structure is the clone. Surprisingly, very little is known about the spread of a clone (spatial distance between clonally related bacteria) and the relationship between spatial distance and genetic distance, especially at very short scale (microhabitat scale), where cell division takes place. Agrobacterium spp. Biovar 1 was chosen because it is a soil bacterial taxon easy to isolate. A total of 865 microsamples 500 μm in diameter were sampled with spatial coordinates in 1 cm3 of undisturbed soil. The 55 isolates obtained yielded 42 ribotypes, covering three genomic species based on amplified ribosomal DNA restriction analysis (ARDRA) of the intergenic spacer 16S-23S, seven of which contained two to six isolates. These clonemates (identical ARDRA patterns) could be found in the same microsample or 1 cm apart. The genetic diversity did not change with distance, indicating the same habitat variability across the cube. The mixing of ribotypes, as assessed by the spatial position of clonemates, corresponded to an overlapping of clones. Although the population probably was in a recession stage in the cube (103 agrobacteria g−1), a high genetic diversity was maintained. In two independent microsamples (500 μm in diameter) at the invasion stage...

The Distribution of Pairwise Genetic Distances: A Tool for Investigating Disease Transmission

Worby, Colin J.; Chang, Hsiao-Han; Hanage, William P.; Lipsitch, Marc
Fonte: Genetics Society of America Publicador: Genetics Society of America
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
56%
Whole-genome sequencing of pathogens has recently been used to investigate disease outbreaks and is likely to play a growing role in real-time epidemiological studies. Methods to analyze high-resolution genomic data in this context are still lacking, and inferring transmission dynamics from such data typically requires many assumptions. While recent studies have proposed methods to infer who infected whom based on genetic distance between isolates from different individuals, the link between epidemiological relationship and genetic distance is still not well understood. In this study, we investigated the distribution of pairwise genetic distances between samples taken from infected hosts during an outbreak. We proposed an analytically tractable approximation to this distribution, which provides a framework to evaluate the likelihood of particular transmission routes. Our method accounts for the transmission of a genetically diverse inoculum, a possibility overlooked in most analyses. We demonstrated that our approximation can provide a robust estimation of the posterior probability of transmission routes in an outbreak and may be used to rule out transmission events at a particular probability threshold. We applied our method to data collected during an outbreak of methicillin-resistant Staphylococcus aureus...

High genetic distance between marine bivalves of the genus mesodesma inhabiting the Atlantic and Pacific coasts of South America

Marins, Luis Fernando Fernandes; Sabaj, Jos?? Alberto Levy
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.02%
Molluscs of the genus Mesodesma are marine bivalves inhabiting the middle littoral on sandy beaches of temperate and subtropical systems, where they usually are the dominant organisms. This genus is represented on South America???s Atlantic coast by Mesodesma mactroides, and by Mesodesma donacium on the Pacific coast. Samples of these species from Brazil and Chile were compared genetically by electrophoresis at 26 isozyme loci. Out of 17 monomorphic loci, 14 were fixed for different alleles. Nine polymorphic loci were found; where 44 alleles were detected, 35 of these were distinct between both species. The statistical analysis showed a Nei???s genetic distance of 1.90. The high genetic distance observed here corroborates the controversy about mesodesmatid systematic problems.

Estudos fenot??picos e moleculares sobre variabilidade gen??tica, qualidade de gr??os e toler??ncia ao estresse por ferro em arroz; Phenotypic and molecular studies on the genetic variability, grain quality and iron stress tolerance in rice

MARINI, Naciele
Fonte: Universidade Federal de Pelotas; Agronomia; Programa de P??s-Gradua????o em Fitomelhoramento; UFPel; BR Publicador: Universidade Federal de Pelotas; Agronomia; Programa de P??s-Gradua????o em Fitomelhoramento; UFPel; BR
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
55.95%
There is a constant need for studies aiming to increase yield and quality traits in rice, which have to consider abiotic stress tolerance and genetic variability. This work had as objective to characterize rice mutant families regarding rice iron stress tolerance and validate a technique based on retrotransposons with the goal of detecting genetic variability in rice. Also, to analyse gene expression of genes involved in starch synthesis in the rice grain. Therefore, nine mutant families were characterized for phenotypic traits and iron content in hydroponic conditions. Twenty genotypes were molecularly characterized with the REMAP technique and three cultivars were analysed the profiled for starch biosynthesis related gene expression by qRT-PCR. The results obtained demonstrate that the genotypes BR-IRGA 409 and BRS7-Taim characterized as sensitive presented a higher accumulation of Fe2+ in the shoots. The mutant families CGF-Z-M9-444CD, CGF-Z-M9-328 and CGF-Z-M9-243, were ranked in this study as tolerant. The genotype CGF-Z-M9-444CD was one of the mutants that accumulated less iron in the tissues under stress conditions, being also characterized as resistant in the phenotypic analysis. The variables root length, number of roots, iron...

Caracteriza????o morfol??gica e dist??ncia gen??tica entre variedades de pimentas; Morphological characterization and genetic distance among pepper varieties

NEITZKE, Raquel Silviana
Fonte: Universidade Federal de Pelotas; Agronomia; Programa de P??s-Gradua????o em Fitomelhoramento; UFPel; BR Publicador: Universidade Federal de Pelotas; Agronomia; Programa de P??s-Gradua????o em Fitomelhoramento; UFPel; BR
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
56.04%
Peppers and sweet peppers from Capsicum genus show great genetic divergence and are an important part of the spice and fresh vegetable market in Brazil. They are closely related to the richness of Brazilian culture and belong to biodiversity patrimony, being cultivated in a huge variety of types, sizes, colors, flavors and pungencies. The success in a plant breeding program is dependent of the amplitude of genetic basis disposable. Characterization activities are very important to promote the use of germplasm by breeders. The objective of this work was to characterize and estimate genetic distance among C. baccatum landraces, using qualitative multicategorical morphological descriptors, and among accessions with ornamental potential from Capsicum Gene Bank of Embrapa Clima Temperado, using qualitative and quantitative morphological descriptors. Results indicate that use of multicategorical data was efficient to study genetic divergence among accessions of C. baccatum. Characterization of accessions with ornamental potential using qualitative descriptors was more adequate to form the groups. The grouping methods used in the study of genetic distance by quantitative descriptors were partially concordant. Results showed large genetic dissimilarity in evaluated germplasm...

Genetic distance detected with RAPD markers among selected Australian commercial varieties and boron-tolerant exotic germplasm of pea (Pisum sativum L.)

Bagheri Kazemabad, A.; Paull, J.; Langridge, P.; Rathjen, A.
Fonte: Kluwer Academic Publishers Publicador: Kluwer Academic Publishers
Tipo: Artigo de Revista Científica
Publicado em //1995 EN
Relevância na Pesquisa
55.95%
The optimisation of polymerase chain reaction (PCR) for random amplified polymorphic DNA (RAPD) analysis in pea was investigated and the results were applied to an analysis of five representative Australian varieties and five selected boron-tolerant accessions derived from different geographical regions. Genotypes were compared using 34 random primers (Operon Technologies, Alameda, CA) which generated 180 polymorphic bands. Genetic similarity among genotypes was estimated on the basis of the percentage of common bands between genotypes and a dendrogram was constructed by the unweighted pair grouping method. A pattern of RAPD reaction corresponding to two main groups was discerned. The genetic divergence between Australian varieties and the boron-tolerant accessions suggests an intensive back-crossing programme would be required to transfer boron tolerance to a locally adapted genetic background. Our results show RAPD to be useful for clarifying phylogenic relationships within a species and also to provide useful genetic markers for varietal identification in pea.; A. Bagheri, J. G. Paull, P. Langridge and A. J. Rathjen

Fluorescent amplified fragment length polymorphism (fAFLP) analyses and genetic diversity in Litopenaeus vannamei (Penaeidae)

Gonçalves, Michelle Mantovani; Lemos, Manoel Victor Franco; Galetti Jr., Pedro Manoel; de Freitas, Patrícia Domingues; Neto, Manuel Antonio Andrade Furtado
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 267-270
ENG
Relevância na Pesquisa
55.99%
The Pacific white shrimp, Litopenaeus vannamei (Penaeidae), represents about 95% of all Brazilian shrimp production. The Brazilian L. vannamei foundation broodstock was made up of specimens collected from different American Pacific sites, but little information was collected on the genetic structure of the broodstock. We used the fluorescence amplified fragment length polymorphism (fAFLP) method to study the genetic diversity of L. vannamei broodstock lines 03CMF1 and 03CBF1 originally produced by breeder-shrimps imported mainly from Panama and Ecuador, although wild individuals from other localities may also have been used in producing these two lines. Our results showed a total of 93 polymorphic bands ranging from 50 to 500 bp, the mean Nei's genetic diversity calculated for the total sample was 13.4% and identity and genetic distance analyses indicated high genetic homogeneity within and between both the broodstock lineages studied which suggests that they had similar genetic structure. These results may represent an important tool for the appropriate management of L. vannamei broodstocks. Copyright by the Brazilian Society of Genetics.

Estimation of genetic distance among genotypes of caraway (Carum carvi L.) using RAPD-PCR

Seidler-Łożykowska,Katarzyna; Kuczyńska,Anetta; Mikołajczyk,Katarzyna; Nowakowska,Joanna; Bocianowski,Jan
Fonte: Editora da Universidade Estadual de Maringá - EDUEM Publicador: Editora da Universidade Estadual de Maringá - EDUEM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
66.08%
In order to estimate genetic diversity among starting materials and breeding strains of caraway, a collection of 17 accessions from botanical gardens in Europe, two cultivars 'Rekord' and 'Kończewicki', and four own breeding strains were analyzed by RAPD-PCR. The representative samples, each of five individual plants of accession, cultivar or strain, were taken from young rosette leaves. Forty of Genset Oligos RAPD primers were used for analysis and eight of them produced clear and reproducible banding patterns. In total, 62 banding patterns were obtained revealing 23 polymorphic bands, whereas the number of polymorphic bands ranged from two to four for one primer. The GS12 and GS43 primers generated two polymorphic bands, while each of the GS8, GS21, GS22, GS41 and GS53 primers generated three bands. The GS53 primer was the most informative one, revealing 60% of the estimated polymorphism. The estimated value of genetic distance ranged from 0.22 to 0.67. The lowest genetic distance was found between accessions from Cluj and Lousanne (0.22). The highest genetic distance was estimated between accession from Berlin and the strain no. 6 of cultivar 'Kończewicki' (0.67). UPGMA cluster analysis, based on eight RAPD primers, categorized the analyzed genotypes into four groups.

Molecular marker heterozygosities and genetic distances as correlates of production traits in F1 bovine crosses

Tambasco-Talhari,Daniella; Alencar,Maurício Mello de; Paz,Cláudia Cristina Paro de; Cruz,Geraldo Maria da; Rodrigues,Armando de Andrade; Packer,Irineu Umberto; Coutinho,Luiz Lehmann; Regitano,Luciana Correia de Almeida
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2005 EN
Relevância na Pesquisa
56.13%
Several studies have investigated the relationship between heterozygosity, genetic distance and production traits. The objective of the present study was to evaluate the influence of the degree of heterozygosity and genetic distance on growth, carcass and reproductive related features in F1 bovine crosses. We tested 10 polymorphic markers in 330 purebred cattle (Nelore, Canchim, Aberdeen Angus and Simental) and 256 crossbred cattle belonging to four crossbred groups. Individual heterozygosities (Hi) and multilocus genetic similarity (Dm) were estimated and used in correlation analysis against individual phenotypic measurements. Significant (p < 0.05) Hi effects occurred for birth weight, 15 to 18 month weight, hot carcass weight and longissimus rib eye area. The extent to which increased heterozygosity (deltaH) in F1 crosses can be predicted from the genetic distance of parental breeds was also investigated using Nei's standard genetic distance (Ds) and standard heterozygosity (Hs). High correlations were found between deltaHi, deltaHs and the Ds of the parental breeds. Our results suggest that heterozygosity of the ten molecular markers used in this study may affect live weight during at least one growth phase. Parental genetic distance was a suitable predictor of the degree of progeny heterozygosity.

Predicting performance of soybean populations using genetic distances estimated with RAPD markers

Barroso,Paulo Augusto Vianna; Geraldi,Isaias Olívio; Vieira,Maria Lúcia Carneiro; Pulcinelli,Carlos Eduardo; Vencovsky,Roland; Dias,Carlos Tadeu dos Santos
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2003 EN
Relevância na Pesquisa
55.95%
In order to verify whether genetic distance (GD) is associated with population mean (PM), genetic variance (GV) and the proportion of superior progenies generated by each cross in advanced generations of selfing (PS), the genetic distances between eight soybean lines (five adapted and three non-adapted) were estimated using 213 polymorphic RAPD markers. The genetic distances were partitioned according to Griffing's Model I Method 4 for diallel analysis, i.e., GDij = GD+ GGDi+ GGDj + SGDij. Phenotypic data were recorded for seed yield and plant height for 25 out of 28 populations of a diallel set derived from the eight soybean lines and evaluated from F2:8 to F2:11 generations. No significant correlation for seed yield was detected between GD and GV, while negative correlations were detected between GD and PM and between GD and PS (r = -0.74** and -0.75**, respectively). Similar results were observed for the correlation between GGDi + GGDj and PM and between GGDi + GGDj and PS (r = -0.78** and -0.80**, respectively). No significant correlation was detected for plant height. The magnitudes of the correlations for seed yield were high enough to allow predictions of the potential of the populations based on RAPD markers.

Genetic diversity between herds of Alpine and Saanen dairy goats and the naturalized Brazilian Moxotó breed

Araújo,Adriana Mello de; Guimarães,Simone Eliza Facioni; Machado,Thea Mírian Medeiros; Lopes,Paulo Sávio; Pereira,Carmen Silva; Silva,Francisco Luiz Ribeiro da; Rodrigues,Marcelo Teixeira; Columbiano,Virgínia de Souza; Fonseca,Cleusa Graça da
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 EN
Relevância na Pesquisa
55.96%
Brazilian naturalized goat breeds are adapted to the semiarid conditions prevalent in the Northeast region of the country (which has the largest Brazilian goat heard) and represent an as yet uninvestigated source of genetic diversity. Currently, imported goat breeds are crossed with Brazilian naturalized goat breeds, endangering the genetic potential of the naturalized breeds. We used 11 microsatellite markers to determine the genetic diversity among imported (non-naturalized) dairy Alpine and Saanen goats and naturalized Brazilian Moxotó goats. We genotyped 292 goats from three herds (one private, one from the University of Minas Gerais and the Moxotó conservation herd from Embrapa Caprinos) and found that the general heterozygosity was 0.6952 for Alpine, 0.7043 for Saanen and 0.4984 for Moxotó goats. The number of alleles ranged from 5 (INRA005) to 11 (BM3205), with an average of 7 alleles per locus in the imported breeds and 3.5 alleles per locus in the Moxotó breed. Mean differentiation between populations was higher for herds (F ST S = 0.0768) than for breeds (F ST P = 0.0263), indicating similarity between the imported breeds and the existence of crosses between them. Nei's genetic distance was highest between the Moxotó breed and the imported breeds. These indicate that further studies using these molecular markers would be fruitful.

Number of ancestral human species: a molecular perspective

Curnoe, Darren; Thorne, Alan
Fonte: Gustav Fischer Verlag Publicador: Gustav Fischer Verlag
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.1%
Despite the remarkable developments m molecular biology over the past three decades, anthropological genetics has had only limited impact on systematics in human evolution. Genetics offers the opportunity to objectively test taxonomies based on morphology and may be used to supplement conventional approaches to hominid systematics. Our analyses, examining chromosomes and 46 estimates of genetic distance, indicate there may have been only around 4 species on the direct line to modern humans and 5 species in total. This contrasts with current taxonomies recognising up to 23 species. The genetic proximity of humans and chimpanzees has been used to suggest these species are con-generic. Our analysis of genetic distances between them is consistent with this proposal. It is time that chimpanzees, living humans and all fossil humans be classified m Homo. The creation of new genera can no longer be a solution to the complexities of fossil morphologies. Published genetic distances between common chimpanzees and bonobos, along with evidence for interbreeding, suggest they should be assigned to a single species. The short distance between humans and chimpanzees also places a strict limit on the number of possible evolutionary 〈side branches〉 that might be recognised on the human lineage. All fossil taxa were genetically very close to each other and likely to have been below congeneric genetic distances seen for many mammals. Our estimates of genetic divergence suggest that periods of around 2 million years are required to produce sufficient genetic distance to represent speciation. Therefore...