Genome-wide identification and characterization of the WOX gene family in Brassica juncea / 生物工程学报

The WUSCHEL related-homeobox (WOX) family is one of the plant-specific transcription factor families, playing important roles in plant growth and development. In this study, 51 WOX gene family members were identified from the genome data of Brassica juncea by searching and screening with HUMMER, Smart and other software. Their protein molecular weight, amino acids numbers, and isoelectric point were analyzed by using Expasy online software. Furthermore, bioinformatics software was used to systematically analyze the evolutionary relationship, conservative region, and gene structure of the WOX gene family. The mustard WOX gene family was divided into three subfamilies: ancient clade, intermediate clade, and WUS clade/modern clade. Structural analysis showed that the type, organization form and gene structure of the conservative domain of WOX transcription factor family members in the same subfamily were highly consistent, while there was a certain diversity among different subfamilies. 51 WOX genes are distributed unevenly on 18 chromosomes of mustard. Most of the promoters of these genes contain cis acting elements related to light, hormone and abiotic stress. Using transcriptome data and real-time fluorescence quantitative PCR (qRT-PCR) analysis, it was found that the expression of mustard WOX gene was spatio-temporal specific, among which BjuWOX25, BjuWOX33, and BjuWOX49 might play an important role in the development of silique, and BjuWOX10, BjuWOX32, and BjuWOX11, BjuWOX23 respectively might play an important role in the response to drought and high temperature stresses. The above results may facilitate the functional study of mustard WOX gene family.

Application of virus-induced gene silencing technology to investigate the phytochrome metabolism mechanism: a review / 生物工程学报

Color is an important indicator for evaluating the ornamental traits of horticultural plants, and plant pigments is a key factor affecting the color phenotype of plants. Plant pigments and their metabolites play important roles in color formation of ornamental organs, regulation of plant growth and development, and response to adversity stress. It has therefore became a hot topic in the field of plant research. Virus-induced gene silencing (VIGS) is a vital genomics tool that specifically reduces host endogenous gene expression utilizing plant homology-dependent defense mechanisms. In addition, VIGS enables characterization of gene function by rapidly inducing the gene-silencing phenotypes in plants. It provides an efficient and feasible alternative for verifying gene function in plant species lacking genetic transformation systems. This paper reviews the current status of the application of VIGS technology in the biosynthesis, degradation and regulatory mechanisms of plant pigments. Moreover, this review discusses the potential and future prospects of VIGS technology in exploring the regulatory mechanisms of plant pigments, with the aim to further our understandings of the metabolic processes and regulatory mechanisms of different plant pigments as well as improving plant color traits.

Advances on the microbial synthesis of plant-derived diterpenoids / 生物工程学报

Natural plant-derived diterpenoids are a class of compounds with diverse structures and functions. These compounds are widely used in pharmaceuticals, cosmetics and food additives industries because of their pharmacological properties such as anticancer, anti-inflammatory and antibacterial activities. In recent years, with the gradual discovery of functional genes in the biosynthetic pathway of plant-derived diterpenoids and the development of synthetic biotechnology, great efforts have been made to construct a variety of diterpenoid microbial cell factories through metabolic engineering and synthetic biology, resulting in gram-level production of many compounds. This article summarizes the construction of plant-derived diterpenoid microbial cell factories through synthetic biotechnology, followed by introducing the metabolic engineering strategies applied to improve plant-derived diterpenoids production, with the aim to provide a reference for the construction of high-yield plant-derived diterpenoid microbial cell factories and the industrial production of diterpenoids.

Advances of miRNA-mediated regulatory roles in plant-microbe interaction / 生物工程学报

There are many bidirectional communication and crosstalk between microbes and host plants. The plant-pathogen interaction directly affects the survival of host plants, while the interaction between plants and their probiotics benefits both. Plant miRNA responds quickly to pathogenic or beneficial microbes when they enter the plant tissues, while microbes also produce miRNA-like RNA (milRNA) to affect plant health. These means miRNA or milRNA is an important fast-responding molecular mediator in plant-microbe interactions, and these internal mechanisms have been better understood in recent years. This review summarized the regulatory roles of miRNA in plant-pathogens and plant-probiotics interaction. The regulatory role of miRNA in disease resistance of host plants during plant-pathogens interaction, and the regulatory role of miRNA in promoting host growth and development during plant-probiotics interaction, as well as the cross-kingdom regulatory role of milRNA in host plants, were discussed in-depth.

Advances in the biosynthesis of tetrapyrrole compounds / 生物工程学报

Tetrapyrrole compounds are a class of compounds with important functions. They exist in living organisms and have been widely used in agriculture, food, medicine, and other fields. The cumbersome process and high cost of chemical synthesis, as well as the shortcomings of unstable quality of animal and plant extraction methods, greatly hampered the industrial production and applications of tetrapyrrole compounds. In recent years, the rapid development of synthetic biology has provided new tools for microorganisms to efficiently synthesize tetrapyrrole compounds from renewable biomass resources. This article summarizes various strategies for the biosynthesis of tetrapyrrole compounds, discusses methods to improve its biosynthesis efficiency and future prospects, with the aim to facilitate the research on biosynthesis of tetrapyrrole compounds.

Oxidosqualene cyclases in triterpenoids biosynthesis: a review / 生物工程学报

Triterpenoids are one of the most diverse compounds in plant metabolites, and they have a wide variety of physiological activities and are of important economic value. Oxidosqualene cyclases catalyze the cyclization of 2, 3-oxidosqualene to generate different types of sterols and plant triterpenoids, which is of great significance to the structural diversity of natural products. However, the mechanism of the diversified cyclization of 2, 3-oxidosqualene catalyzed by oxidosqualene cyclases remains unclear. This review summarized the research progress of oxidosqualene cyclases from the aspects of catalytic function, molecular evolutionary relationship between genes and proteins, protein structure, molecular simulation and molecular calculations, which may provide a reference for protein engineering and metabolic engineering of triterpene cyclase.

The role of SnRK2 in the response to stress, the growth and development of plants / 生物工程学报

Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) is a specific Ser/Thr protein kinase in plants. SnRK2 can regulate the expression of downstream genes or transcription factors through phosphorylation of substrates to achieve stress resistance regulation in different tissue parts, and make plants adapt to adverse environment. SnRK2 has a small number of members and a molecular weight of about 40 kDa, and contains a conserved N-terminal kinase domain and a divergent C-terminal regulatory domain, which plays an important role in the expression of enzyme. This review summarized the recent research progresses on the discovery, structure, and classification of SnRK2, and its function in response to various stresses and in regulating growth and development, followed by prospecting the future research direction of SnRK2. This review may provide a reference for genetic improvement of crop stress resistance.

Advances in the research of microRNA in Orchidaceae / 生物工程学报

As a class of small non-coding RNAs, microRNA (miRNA) is widely present and plays important regulatory roles in plant growth, development and stress response. Based on the mechanism of miRNAs in plants, we review the identification of miRNAs in some genera of Orchidaceae, the specific functions of several miRNAs and other relevant studies on miRNAs in the last decade, in order to provide a reference for better understanding function and regulatory network of small RNAs in orchids.

Plant prime editing technique: a new genome editing tool for plants / 生物工程学报

The CRISPR/Cas9 based prime editing (PE) technique enables all 12 types of base substitutions and precise small DNA deletions or insertions without generating DNA double-strand breaks. Prime editing has been successfully applied in plants and plays important roles in plant precision breeding. Although plant prime editing (PPE) can substantially expand the scope and capabilities of precise genome editing in plants, its editing efficiency still needs to be further improved. Here, we review the development of PPE technique, and introduce structural composition, advantages and limitations of PPE. Strategies to improve the PPE editing efficiency, including the Tm-directed PBS length design, the RT template length, the dual-pegRNA strategy, the PlantPegDesigner website, and the strategies for optimizing the target proteins of PPE, were highlighted. Finally, the prospects of future development and application of PPE were discussed.

Short Tandem Repeats in plants: genomic distribution and function prediction

BACKGROUND: Short Tandem repeats (STRs) existed as popular elements in both eukaryotic and prokaryotic genomes. RESULTS: In this study, we analyzed the characteristics, distributions, and motif features of STRs within whole-genomes of 140 plant species. The results showed that STR density was negatively correlated with the genome size. Hexanucleotide repeat was the most abundant type of STRs. The distribution of algae shows a preference different from that of other plants. By analyzing GC contents of STRs and genome, it was concluded that STR motif was influenced by GC contents. Analysis of the long STRs in genome (length 1000 bp) found that dicots have the more long STRs. For STR types, di- and tri-nucleotide accounted for the highest proportion. Analyzing and designing long STRs in CDS (length 500 bp) was to verify the role of long STRs in Gossypium hirsutum TM-1 and Solanum tuberosum. By comparing the long STRs found in Fragaria x ananassa with other species, some evolutionary characteristics of the long STRs were obtained. CONCLUSIONS: We got the characteristics, distribution, and motif features of STRs in the whole genome of 140 plants and obtained some evolutionary characteristics of long STRs. The study provides useful insights into STR preference, characteristics, and distribution in plants.

Phylogenetic relationships of plant species from the flowering desert of the Atacama Region / Relaciones filogenéticas de especies de plantas que crecen en el desierto florido de la Región de Atacama

Every 3 to 7 year angiosperms species of the flowering desert appear in the Atacama Region of Chile, as a result of the climatic phenomenon "El Niño". Our objective was to evaluate the universality of matK and rbcL barcode markers of these species, and validate their taxon through phylogenetic relationships. Argemone hunnemannii, Oenothera coquimbensis, Malesherbia humilis, Leucocoryne appendiculata, Loasa elongata, Nicotiana solanifolia, Stachys grandidentata, Aristolochia chilensis, Alstroemeria kingii and Adesmia eremophila, almost all classified as endemic to Chile, were collected in Pan de Azúcar and Llanos de Challe National Park (Atacama Region, Chile) at the end of October 2017. The phylogeny of these ten angiosperm species from the flowering desert was analyzed using rbcL and matK markers with the maximum likelihood and Bayesian inference methods. The results showed that 70% of the species can be distinguished with the matK or rbcL locus, however, 100% were distinguished using both loci. The phylogenetic results showed that the species formed clades with high reliability and high support with both the matK and rbcL genes, when comparing our results with sequences obtained from GenBank. The matK and rbcL genes are efficient markers for analyzing phylogenetic relationships and validating the taxonomy of flowering species.

Las especies de angiospermas del Desierto Florido de la Región de Atacama de Chile aparecen cada 3 a 7 años, influenciado por el fenómeno climático "El Niño". Nuestro objetivo fue evaluar la universalidad de los marcadores de código de barra matK y rbcL de estas especies, y validar su taxón por medio de relaciones filogenéticas. Las especies Argemone hunnemannii, Oenothera coquimbensis, Malesherbia humilis, Leucocoryne appendiculata, Loasa elongata, Nicotiana solanifolia, Stachys grandidentata, Aristolochia chilensis, Alstroemeria kingii y Adesmia eremophila son clasificadas la mayoría endémicas de Chile. Estas especies fueron colectadas en el Parque Nacional Pan de Azúcar y Llanos de Challe, Región de Atacama, Chile. La colecta se realizó a fines de octubre de 2017. Con los marcadores rbcL y matK se analizó la filogenia con los métodos máxima verosimilitud e inferencia bayesiana en diez especies de angiosperma del Desierto Florido. Los resultados mostraron que el 70% de las especies pueden ser distinguidas con un locus matK o rbcL, sin embargo, el 100% se distinguió usando ambos locus. Los resultados filogenéticos mostraron que las especies formaron clados con alta fiabilidad y alto soporte tanto con los genes matK y rbcL, al comparar con accesos de secuencias obtenidas de GenBank. Lo genes matK y rbcL son marcadores eficientes para analizar relaciones filogenéticas y validar el taxón de las especies de flor.

Current development of gene editing / 生物工程学报

As the breakthrough in gene editing, represented by CRISPR/Cas9, gene manipulations now are more maneuverable, economically feasible and time saving. It is possible for China to catch an overtaking in researching and industrializing of downside sections (especially the application of plant gene editing), also the incubation of professional companies in gene editing fields. For this consideration, it is necessary and urgent to find the key demands and potential application for gene editing in China. Questionnaire and statistic analysis were carried out to find the key demands and the most potential application fields of the development for gene editing. Firstly, an ordered multi-classification Logistic regression model was established following with dependent variable analysis. Eight out of 24 questionnaires questions in 4 categories were regarded as independent variables with significance test. Then, regression model based on ordered multi-classification logistic method was established to analyze the specific impact of different options on the development of gene editing. The results showed that most researchers in the field of gene editing take the view that development of potential competitive advantages lies in the field of plant science. The results also showed that major gene editing experts believe more attention should be paid on how to carry out technology industrialization while focusing on basic technology development, as well as the development of potential competitive advantages of gene editing technology in plant field. To promote the development of gene editing in China, not only the participation of scientific research institution was needed, but also the synergy of various forces both universities and governments. It is urgent both properly guiding public opinion on gene editing and establishing a national safety standard system. At the same time, the key point of technology risk avoidance should be put on biological weapons and bioterrorism, gene editing related infectious disease, and the potential risk of species genetic change on the ecological environment, etc.

Determination of Place of Residence Using the Gene Information of Plants Carried by the Human Body / 法医学杂志

Objective To identify the plant species using the DNA sequence of plant pollen from lung tissues of a unidentified body, infer the possible long-term places of residence of the deceased according to the distribution area of the pollen in the lung tissues, therefore narrow the scope of criminal investigation and provide clues for case solving. Methods Lung tissues were extracted from the deceased, total DNA was extracted by the mCTAB method. Gene fragments of the two plant DNA barcodes, matK and rbcL, were acquired using specific primers for amplification, then sequenced. The DNA sequences of target gene fragments were acquired through bioinformatics analysis. The sequences were combined with reference sequence data. Phylogenetic analysis was made to identify the species that the DNA sequences belonged to. The places where the deceased could have lived for a long time were inferred, according to the distribution information of plant species. Results Gene fragments of 32 plant species which belonged to 31 genera of 27 families were in the lung tissues of the deceased. Among them, plants of 9 genera that had certain indicative function were mainly endemic plants from Hainan, Guangdong, Guangxi and Yunnan. These results showed that the deceased may have stayed in these areas for a long time before death. After further investigation, the victim was confirmed to have come from a county in southern Guangxi, which was in accordance with the research results. Conclusion The method of using gene information of plants from lung tissues of human bodies to infer places of residence can assist inference of the places where the deceased could have lived for a long time. The present study may also provide new ideas for locating sources of the corpses in cases with unidentified victims.

Phylogenetic structure is determined by patch size in rock outcrop vegetation on an inselberg in the northern Amazon region / Estrutura filogenética é determinada pelo tamanho de manchas de vegetação sobre afloramento rochoso em um inselberg na região norte da Amazônia

Although inselbergs from around the world are iconic ecosystems, little is known on the underlying mechanisms of community assembly, especially in their characteristic patchy outcrop vegetation. Environmental constraints are expected to cause phylogenetic clustering when ecological niches are conserved within evolutionary lineages. We tested whether vegetation patches from rock outcrops of the Piedra La Tortuga Natural Monument, in the northern Amazon region, are phylogenetically clustered, indicating that environmental filtering is the dominant driver of community assemblage therein. We classified all patches according to their size as very small (< 1 m2), small (1-4 m2), medium-sized (4-8 m2), and large patches (8-15 m2). From each class, we randomly selected 10 patches, totalizing 40 patches covering 226 m2. All individuals found in the 40 isolated patches were identified to the species level. We also correlated measurements of phylogenetic community structure with patch size. We found that species from patches are restricted to the clades monocots, fabids, malvids, and lamiids. We conclude that vegetation in this rock outcrop is phylogenetically clustered. Furthermore, we found that phylogenetic turnover between pairs of patches increases with patch size, which is consistent with a scenario of higher environmental stress in smaller patches. Further research is necessary to identify nurse species in inselberg vegetation, which is pivotal for conservation and restoration of this particular ecosystem.

Ainda que os inselbergs ao redor do mundo sejam ecossistemas icônicos, pouco se sabe sobre os mecanismos subjacentes que estruturam suas comunidades vegetais, especialmente nas manchas de vegetação sobre afloramentos rochosos. Espera-se que as restrições ambientais causem agrupamento filogenético quando os nichos ecológicos são conservados dentro das linhagens evolutivas. Nós testamos se as manchas de vegetação dos afloramentos rochosos do Monumento Natural Piedra La Tortuga, no norte da região amazônica, apresentam indicadores filogenéticos de que a filtragem ambiental é o principal direcionador da estruturação da comunidade. Classificamos todas as manchas de acordo com seu tamanho como muito pequenas (<1 m2), pequenas (1-4 m2), médias (4-8 m2) e grandes (8-15 m2). Selecionamos aleatoriamente 10 manchas em cada classe de tamanho, totalizando 40 manchas cobrindo 226 m2. Todos os indivíduos encontrados nas 40 manchas foram identificados ao nível de espécie. Correlacionamos as medidas da estrutura filogenética da comunidade com o tamanho das manchas e encontramos que as espécies das manchas são restritas aos clados das monocotiledôneas, fabídeas, malvídeas e lamiídeas. Concluímos que a vegetação neste afloramento rochoso é agrupada filogeneticamente. Além disso, encontramos que o turnover filogenético entre pares de manchas aumenta com o tamanho da mancha, o que é consistente com um cenário de alto estresse ambiental nas manchas menores. São necessárias mais pesquisas para identificar espécies facilitadoras, que são fundamentais para a conservação e restauração destes ecossistemas.

Diversity of Drimia indica (Roxb.) Jessop and its relationship to Drimia nagarjunae using phenotypic traits and molecular markers.

In the present study, we explored the diversity of different accessions of Drimia indica and its relation to D. nagarjunae using phenotypic traits and molecular markers. Twenty populations of D. indica, from different parts of India, were compared with D. nagarjunae, an endangered medicinal plant collected from Andhra Pradesh, India. Two species showed appreciable phenotypic diversity in number of leaves, leaf indices, bulb circumference, bulb length and length of roots. The principal component analysis (PCA) performed on above 5 quantitative characters to determine relationship among populations, has distinguished D. nagarjunae from D. indica phenotypically. Genetic diversity was analysed using RAPD and ISSR primers which produced reproducible bands in 8 RAPD and 3 ISSR primers. A total of 89 amplicons were observed, of which 69 (77.53 %) were polymorphic. Cluster diagram and phylogenetic linkage showed that D. nagarjunae formed a separate cluster, showing no similarity with any of the populations of D. indica. The molecular marker data correlated with PCA of phenotypic traits. Current investigations have demonstrated that the statistical approach for phenotypic characters and molecular markers analysis can be applied to study diversity in Drimia species.

Toxicity and genotoxicity of water and sediment from streams on dotted duckweed (Landoltia punctata) / Toxicidade e genotoxicidade da água e sedimentos dos córregos em lentilha d'água (Landoltia punctata)

Most rivers are used as a source to supply entire cities; the quality of water is directly related to the quality of tributaries. Unfortunately men have neglected the importance of streams, which receive domestic and industrial effluents and transport nutrients and pesticides from rural areas. Given the complexity of the mixtures discharged into these water bodies, this study aimed to evaluate the quality of water and sediment of ten tributaries of Pirapó River, in Maringá, Paraná State, Brazil. To this end, the free-floating macrophyte Landoltia punctata (G. Meyer) Les & D.J.Crawford was used as test organism in microcosm, and the toxicity of water and sediment samples was evaluated by the relative growth rate, dry/fresh biomass ratio, and genotoxic effects (comet assay). Samples of water and sediment of each stream were arranged in microcosms with L. punctata. Seven days later, plants were collected for analysis. Nutrient levels were higher than the reference location, indicating eutrophication, but the results indicated a toxic effect for only three streams, and a genotoxic effect for all streams.

Muitos rios são utilizados como fonte de abastecimento de cidades inteiras e a qualidade de suas águas está relacionada diretamente à qualidade de seus afluentes. Infelizmente córregos têm sua importância negligenciada pelo homem sendo alvo de despejos domésticos e industriais e também do carreamento de nutrientes e pesticidas das áreas rurais. Diante da complexidade das misturas que atingem estes corpos d'água, o presente estudo teve por objetivo avaliar a qualidade da água e do sedimento de dez afluentes do rio Pirapó no município de Maringá, Estado do Paraná. Utilizou-se a macrófita aquática flutuante Landoltia punctata (G. Meyer) Les & D.J.Crawford como organismo teste em microcosmos, sendo que a toxicidade das amostras de água e sedimento foi avaliada pela taxa de crescimento relativo, pelo índice de biomassa seca por fresca, e pelos efeitos genotóxicos (ensaio de cometa). Amostras de água e sedimento de cada córrego foram dispostos em microcosmos com L. punctata. Após 7 dias as plantas foram coletadas para as análises. Os níveis de nutrientes foram maiores que o do local de referência indicando eutrofização; porém, os resultados indicaram efeito tóxico em apenas três dos córregos e genotóxico em todos os córregos.

Chemical Genomics in Plant Biology.

Chemical genomics is a newly emerged and rapidly progressing field in biology, where small chemical molecules bind specifically and reversibly to protein(s) to modulate their function(s), leading to the delineation and subsequent unravelling of biological processes. This approach overcomes problems like lethality and redundancy of classical genetics. Armed with the powerful techniques of combinatorial synthesis, high-throughput screening and target discovery chemical genomics expands its scope to diverse areas in biology. The well-established genetic system of Arabidopsis model allows chemical genomics to enter into the realm of plant biology exploring signaling pathways of growth regulators, endomembrane signaling cascades, plant defense mechanisms and many more events.

Genetic architecture of purple pigmentation and tagging of some loci to SSR markers in pearl millet, Pennisetum glaucum (L.) R. Br.

This report describes the construction of integrated genetic maps in pearl millet involving certain purple phenotype and simple sequence repeat (SSR) markers. These maps provide a direct means of implementing DNA marker-assisted selection and of facilitating "map-based cloning" for engineering novel traits. The purple pigmentation of leaf sheath, midrib and leaf margin was inherited together 'en bloc' under the control of a single dominant locus (the 'midrib complex') and was inseparably associated with the locus governing the purple coloration of the internode. The purple panicle was caused by a single dominant locus. Each of the three characters (purple lamina, purple stigma and purple seed) was governed by two complementary loci. One of the two loci governing purple seed was associated with the SSR locus Xpsmp2090 in linkage group 1, with a linkage value of 22 cM, while the other locus was associated with the SSR locus Xpsmp2270 in linkage group 6, with a linkage value of 23 cM. The locus for purple pigmentation of the midrib complex was either responsible for pigmentation of the panicle in a pleiotropic manner or was linked to it very closely and associated with the SSR locus Xpsmp2086 in linkage group 4, with a suggestive linkage value of 21 cM. A dominant allele at this locus seems to be a prerequisite for the development of purple pigmentation in the lamina, stigma and seed. These findings suggest that the locus for pigmentation of the midrib complex might regulate the basic steps in anthocyanin pigment development by acting as a structural gene while other loci regulate the formation of color in specific plant parts.

Phenotypical, phytochemical and molecular characterization of "capim-carona" [Elionurus muticus (Spreng. ) Kuntze] populations / Caracterização fenotípica, fitoquímica e molecular de populações de Elionurus muticus (Spreng. ) Kuntze (capim-carona)

Elionurus muticus naturally occurs in southern Brazil and its economic potential is due to the presence of essential oils. There are few studies about this genus. Thus, the aim of the present study was to characterize native E. muticus populations. The study was performed with five "capim-carona" populations collected in the state of Rio Grande do Sul, totaling 50 plants grown in pots in the Agronomy School. All five E. muticus populations presented variability for phenotypic traits and phenolic compound concentration. The presence of citral was identified in all populations, except in that from the "Morro da Polícia" region. RAPD analysis showed high variability for these populations, allowing the separation of individuals into five groups according to their geographic origin. The highest variability occurred within each population. Based on the results, the populations from São Borja and Agronomy School can be recommended to be used in breeding programs.

Elionurus muticus ocorre naturalmente no sul do Brasil e o potencial econômico se deve ao fato da presença de óleos essenciais. Poucos estudos têm sido desenvolvidos para este gênero. Sendo assim, o presente trabalho teve como objetivo caracterizar populações nativas de E. muticus. O trabalho foi realizado com cinco populações de capim-carona coletadas no Rio Grande do Sul, totalizando 50 plantas cultivadas em vasos na Faculdade de Agronomia. As cinco populações de E. muticus apresentaram variabilidade para os caracteres fenotípicos e para concentração de compostos fenólicos. A presença de citral foi identificada em todas as populações, exceto a do Morro da Polícia. A análise de RAPD demonstrou elevada variabilidade para as populações, permitindo a separação dos indivíduos em cinco grupos, sendo possível, de modo geral, agrupá-los de acordo com a origem geográfica. Observou-se também que a maior variabilidade ocorreu dentro de cada população. Os resultados indicaram que as populações São Borja e Faculdade de Agronomia podem ser recomendadas para a utilização em programas de melhoramento.

Linkage analysis between dominant and co-dominant makers in full-sib families of out-breeding species

As high-throughput genomic tools, such as the DNA microarray platform, have lead to the development of novel genotyping procedures, such as Diversity Arrays Technology (DArT) and Single Nucleotide Polymorphisms (SNPs), it is likely that, in the future, high density linkage maps will be constructed from both dominant and co-dominant markers. Recently, a strictly genetic approach was described for estimating recombination frequency (r) between co-dominant markers in full-sib families. The complete set of maximum likelihood estimators for r in full-sib families was almost obtained, but unfortunately, one particular configuration involving dominant markers, segregating in a 3:1 ratio and co-dominant markers, was not considered. Here we add nine further estimators to the previously published set, thereby making it possible to cover all combinations of molecular markers with two to four alleles (without epistasis) in a full-sib family. This includes segregation in one or both parents, dominance and all linkage phase configurations.