1,721,020 research outputs found
Addressing the molecular bases of heterosis in maize (Zea mays L.)
Full text linkHeterosis is widely exploited in agriculture for the production of high-performing hybrid varieties. However, its genetic and molecular bases still remain unknown. In my PhD thesis I report the results of experiments carried out for contributing to a deeper understanding of the transcriptional mechanisms underlying heterosis in maize. Data are reported in the form of full paper manuscripts. The first manuscript deals with a genome-wide comparison of gene expression in immature ears carried out using cDNA microarray technology on two inbred lines and their heterotic hybrid. The second manuscript reports the expression analysis of intra-specific non-shared genes from large allelic genome segments between two different maize inbred lines, conducted during an 8-months stage in the lab of Antoni Rafalski at DuPont Experimental Station (Wilmington, DE, USA). Finally, results of allele specific expression analysis assessing the relative amount of parental-specific allele transcripts in different tissues within a heterotic maize hybrid are reported in the last manuscript
Towards an alternative high-resolution non-meiotic linkage map of grape (Vitis vinifera L.)
No full textOrigins, genetic organization and transcription of a family of non-autonomous helitron elements in maize
No full textHelitron transposable elements carrying gene fragments were recently discovered in maize. These elements are frequently specific to certain maize lineages. Here we report evidence supporting the involvement of
helitrons in the rapid evolution of the maize genome, in particular in the multiplication of related genic
fragments across the genome. We describe a family of four closely related, non-autonomous maize helitrons
and their insertion sites at four non-allelic genetic loci across the maize genome: two specific to the B73 inbred,
and two to the Mo17 inbred. We propose the phylogeny of this helitron family and provide an approximate
timeline of their genomic insertions. One of these elements, the Mo17-specific helitron on chromosome 1 (bin
1.07), is transcriptionally active, probably as a result of insertion in the vicinity of a promoter. Significantly, it
produces an alternatively spliced and chimeric transcript joining together genic segments of different
chromosomal origin contained within the helitron. This transcript potentially encodes up to four open reading
frames. During the course of evolution, transcribed helitrons containing multiple gene fragments may
occasionally give rise to new genes with novel biochemical functions by a combinatorial assembly of exons.
Thus helitrons not only constantly reshape the genomic organization of maize and profoundly affect its genetic
diversity, but also may be involved in the evolution of gene function
Comparison of Transcription Levels in Immature Ears Between Inbred Lines and Corresponding F1 Hybrid By DNA Microarray Technology
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Production of a multiparental RIL population for high-resolution mapping in maize
No full textThe development of advanced cross designs that might boost the power of detection of the genetic bases of complex traits remain a crucial goal of modern plant genetics. Here we describe the program currently ongoing for the development of an innovative advanced Recombinant Inbred Lines population, aimed at the genetic and molecular dissection of complex traits in maize. Eight maize inbred lines were selected to include a wide genetic variability for the expression of complex
phenotypes and crossed according to a half-diallel design. This genetic material was used as the starting point for producing an extended (>2000) maize 8-ways RIL (8W-RIL) to be used for highresolution
QTL mapping. According to what estimated by The Complex Trait Consortium, which first proposed this model for mouse, such a material should allow mapping QTL with effect size >5% of the total variance to an interval of 0.5 cM using fewer than 1000 lines. Twenty-eight F1 hybrids from the 8x8 half-diallel were crossed so that only crosses between entries with no parents in common (e.g. cross AB x CD) were allowed (but not AB x AD or AB x BF, etc.). Such obtained 4-ways hybrids (210) were bulked in 70 pools, each composed by all the three 4-ways hybrids bearing the same alleles in all possible parent-of-origin cis combinations (e.g.
“ABCD” pool included ABxCD, ACxBD and ADxBC 4-ways hybrids). 8-ways hybrids were then
produced by crossing complementary 4-ways hybrids pools (e.g. ABCD x EFGH, CDFG x ABEH,
etc.). The production of 8W-RIL by single-seed descent is currently at the third selfing generation (8W-RIL F3). Performing two generations of selfing per year, we expect to obtain a 8W-RI F6
mapping population by the end of 2010, whereas the molecular characterization of parental lines is scheduled to start in the fall of 2009. All 2-ways hybrids, 4-ways hybrids and 8-ways highlyrecombinant hybrids plus the parental inbreds will also be available for phenotypic evaluation of complex traits, including heterotic traits
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Mineral nutritional content of 100 g pea seeds as a DV percentage for a 2,000 calories human diet.
No full textMineral nutritional content of 100 g pea seeds as a DV percentage for a 2,000 calories human diet.</p
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