ABSTRACT
Rice is believed to have originated from Indo-China, area between China and India, and then spread throughout the world. The Indochina region mainly includes countries like Thailand, Laos and Vietnam, which are the world’s major rice exporters. Rice varieties grown in this area are highly diverse due to their different environment, ecosystem and climatic conditions. The objective of this study was to evaluate the genetic relationship of Indochina rice varieties using intersimple sequence repeat (ISSR), sequence-related amplified polymorphism (SRAP) and insertion–deletion (InDel) markers. Forty-six rice varieties, including 16, 4,11 and 15 from Thailand, China, Laos and Vietnam, respectively were used in this study. Seventeen of the 20 ISSR primers showed 82.96% polymorphism. At the same time, 17 of the 30 primer pairs of SRAP marker showed clearDNA amplification, which resulted in 84.79% polymorphism. Ninety-seven of 133 InDel markers have about 99.47% polymorphism. Three markers showed average PIC score ranging from 0.20 to 0.26. When the analysis was conducted using UPGMA clustering method, it was found that the combined data from three markers gave a better result than each marker separately. The results from clustering analysis showed that all accessions can be grouped based on their location and can be categorized into two major groups. Useful results from this study could bring substantial benefits and ultimately help the rice breeders to develop elite rice varieties in future.
ABSTRACT
Even when conventional breeding was effective in achieving a continuous improvement in yield, Molecular Genetics tools applied in plant breeding contributed to maximize genetic gain. Thus, the use of DNA technology applied in agronomic improvement gave rise to Molecular Breeding, discipline which groups the different breeding strategies where genotypic selection, based on DNA markers, are used in combination with or in replacement of phenotypic selection. These strategies can be listed as: marker-assisted selection; marker-assisted backcrossing; marker assisted recurrent selection; and genomic selection. Strong arguments have been made about the potential advantages that Molecular Breeding brings, although little has been devoted to discussing its feasibility in practical applications. The consequence of the lack of a deep analysis when implementing a strategy of Molecular Breeding is its failure, leading to many undesirable outcomes and discouraging breeders from using the technology. The aim of this work is to trigger a debate about the convenience of the use of Molecular Breeding strategies in a breeding program considering the DNA technology of choice, the complexity of the trait of agronomic interest to be improved, the expected accuracy in the selection, and the demanded resources.
El mejoramiento convencional ha sido efectivo para lograr una mejora continua en el rendimiento; sin embargo las herramientas de Genética Molecular aplicadas en el fitomejoramiento han contribuido a maximizar la ganancia genética. Es así que el uso de la tecnología de ADN aplicada en la mejora agronómica dio lugar al Mejoramiento Molecular, disciplina que agrupa las diferentes estrategias en las que la selección genotípica, basada en marcadores de ADN, es utilizada en combinación con, o bien en reemplazo de, la selección fenotípica. Estas estrategias se pueden clasificar como: selección asistida por marcadores; retrocruzamiento asistido por marcadores; selección recurrente asistida por marcadores; y selección genómica. Se han presentado fuertes argumentos sobre las potenciales ventajas que aporta el mejoramiento molecular, aunque poco se ha dedicado a discutir la viabilidad de su aplicación práctica. La consecuencia de la falta de un análisis profundo al implementar una estrategia de este tipo puede ser su fracaso, lo que puede derivar en resultados indeseables, desalentando a los fitomejoradores a usar la tecnología. El objetivo de este trabajo es propiciar un debate sobre la conveniencia del uso práctico de estrategias de mejoramiento molecular teniendo en cuenta la tecnología de ADN elegida, la complejidad del rasgo de interés agronómico que se quiere mejorar, la precisión esperada en la selección y los recursos demandados.
ABSTRACT
DNA marker-assisted selection of medicinal plants is based on the DNA polymorphism, selects the DNA sequences related to the phenotypes such as high yields, superior quality, stress-resistance and so on according to the technologies of molecular hybridization, polymerase chain reaction and high-throughput sequencing, and assists the breeding of new cultivars. This study bred the first disease-resistant cultivar of notoginseng "Miaoxiang Kangqi 1" using the technology of DNA marker-assisted selection of medicinal plants and systematic breeding. The disease-resistant cultivar of notoginseng contained 12 special SNPs based on the analysis of Restriction-site Associated DNA Sequencing (RAD-Seq). Among the SNP (record_519688) was related to the root rot-resistant characteristics, which indicated this SNP could serve as genetic markers of disease-resistant cultivars and assist the systematic breeding. Compared to the conventional cultivated cultivars, the incidence rate of root-rot and rust-rot in notoginseng seedlings decreased by 83.6% and 71.8%, respectively. The incidence rate of root-rot respectively declined by 43.6% and 62.9% in notoginseng cultivation for 2 and 3 years compared with those of the conventional cultivated cultivars. Additionally, the potential disease-resistant groups were screened based on the relative SNP, and this model enlarged the target groups and advanced the breeding efficiency. DNA marker-assisted selection of medicinal plants accelerated the breeding and promotion of new cultivars, and guaranteed the healthy development of Chinese medicinal materials industry.
ABSTRACT
Objective Analysis of the genetic structure stability of Brandt ’ s vole ( lasiopodomys brandtii ) in closed colony using microsatellite marker technology.Methods Genomic DNA was extracted from tail tip using high-concentration-salt precipitation methods.Marked with fluorescent tags( Fam) , 7 microsatellite primers were filtered out by PCR, and the DNA structure of three consecutive generations of Brandt’ s vole was analyzed by microsatellite marker. Results By the analysis of the average heterozygosity and polymorphism information content, Brandt’ s vole populations maintaineda closed group of qualified genetic structure.Conclusions The present results show that the closed group of Brandt’ s vole species in our laboratory maintain a stable genetic structure.
ABSTRACT
At the boundary between pharmacognosy and molecular biology, molecular pharmacognosy has developed as a new borderline discipline. This paper reviews the methods, application, and prospect of molecular pharmacognosy. DNA marker is one of genetic markers and some molecular marker methods which have been successfully used for genetic diversity identification and new medicinal resources development. Recombinant DNA technology provides a powerful tool that enables scientists to engineer DNA sequences. Gene chip technique could be used in determination of gene expression profiles, analyses of polymorphisms, construction of genomic library, analysis of mapping, and sequencing by hybridization. Using the methods and theory of molecular biology and pharmacognosy, molecular pharmacognosy represents an extremely prospective branch of pharmacognosy and focuses on the study of systemic growth of medicinal plants, identification and evaluation of germplasm resources, plant metabolomics and production of active compounds. Furthermore, the great breakthrough of molecular pharmacognosy could be anticipated on DNA fingerprint analysis, cultivar improvement, DNA identification, and a global DNA barcoding system in the future.
ABSTRACT
A seringueira [Hevea brasiliensis (Willd. ex. Adr. de Juss) Muell.-Arg.] é uma espécie nativa da região amazônica e compreende a maior fonte produtora de borracha natural do mundo. Na busca de condições mais favoráveis ao cultivo, além da busca pela auto-suficiência na produção de borracha natural, o cultivo da seringueira migrou para outras regiões do país. Objetivou-se, com o presente trabalho, estimar a similaridade genética de genótipos de seringueira, provenientes de regiões distintas do país, Lavras-MG (UFLA) e Campinas-SP (IAC), por meio de marcadores moleculares RAPD. A análise foi efetuada em 41 indivíduos, representados por 17 genótipos diferentes, com base em 19 primers, que geraram 121 fragmentos polimórficos. Os dados foram analisados utilizando o software NTSYS-pc - 2.1, por meio do coeficiente de Dice e pelo método das médias (UPGMA). A similaridade genética entre o material analisado variou de 0,56 a 1,00. Na análise do dendrograma, foram observados 18 grupos. Os clones (RRIM600, GT1, PB235, PL PIM e FX2261), utilizados em diferentes repetições, foram idênticos, quando comparados entre si, entretanto o mesmo não foi observado para os clones identificados como RRIM 701. Os resultados obtidos sugerem que o material avaliado na UFLA é o mesmo implantado no IAC, exceto o RRIM 701, mostrando uma ampla variabilidade genética, disponível para estudos e propagação da cultura.
The rubber tree [Hevea brasiliensis (Willd. ex. Adr. de Juss) Muell.-Arg.] is a native species from Amazon region, and represents the biggest source of natural rubber in the world.. However, the rubber tree culture has had an expansion to other brazilian regions, in search of more favorable conditions for its cultivation and self-sufficiency in natural rubber. The aim of this work was to estimate genetic similarity among rubber tree clones, from different Brazilian regions, Lavras (UFLA) and Campinas (IAC), by using RAPD molecular markers. The analysis was made using 41 individual plants, which represent 17 different clones, based on 19 primers, which raised 121 polymorphic fragments. The data were analysed with NTSYS-pc - 2.1 software, by using Dice coefficient and UPGMA method. Genetic similarity among the materials showed variation from 0,56 to 1,00. In dendogram analysis, 18 groups were observed. The clones RRIM600, GT1, PB235, PLPIM and FX2261 used in different replications, were identical, when compared among themselves. However, results were not the same for the clones identified by RRIM 701. Results suggest that the UFLA material is the same of IAC material, except for RRIM 701, showing wide genetic variability available for studies and culture propagation.
ABSTRACT
A case of neonatal diabetes mellitus is described. The child presented with low birth weight but was normal in appearance. She was acidotic and ketonuria was observed. The HLA typing was DR1 and 3, and insulin autoantibodies were negative. Genetic analysis with polymorphic DNA markers for chromosome 6 indicated biparental inheritance. She required insulin therapy for the control of hyperglycemia, and insulin dependence continues after 8 months of age.