Chromosomal location of genes controlling flavonoid production in hexaploid wheat

Two-dimensional paper chromatography was performed on methanol extracts of leaves of hexaploid bread wheat, Triticum aestivum L. em. Thell. cultivar Chinese Spring, and of the available nullisomic-tetrasomic compensating lines, the tetrasomic lines and the ditelocentric lines. The chromatograms had 27 spots identified as flavonoids and six representing phenolic acids. Some of the areas were complex and contained more than one compound. Four flavonoids were identified as under the control of gene(s) on chromosome arms 1DS, 4DL, 5AS and 6BS. A phenolic glycoside was concluded to be controlled by a gene(s) on chromosome arm 7BL. Gene(s) on chromosome arm 4DL affected the amount of compounds in two other spots, and gene(s) on chromosome arm 4BS reduced the level of all flavonoid compounds. The individual compounds in some of the complex spots may be under the control of gene(s) on homoeologous chromosomes.     

Evolutionary implications of substitution patterns in prolamin genes of Oryza glaberrima (African rice, Poaceae) and related species

Patterns of sequence variation of nuclear genes encoding 10-kDa and 16-kDa prolamin seed storage proteins were examined in Oryza glaberrima (African rice, Poaceae) and O. barthii and compared to available sequences for the genus to assess potential application of these gene families in evolutionary studies. Sequence variation among species in 10-kDa genes was very low. In contrast, the 16-kDa genes have undergone rapid evolution, displaying a larger number of length and point mutations that in some cases result in frame shift or produce truncated protein or pseudogenes. The proportion of nonsynonymous substitution is high in both genes. Although nonsynonymous mutations did not alter the overall profile of the protein, pronounced shifts in proportions of some amino acids were evident and could have systematic application. The data provide support for a proposed direct evolution of the Asian (O. sativa) and African rice from O. rufipogon and O. barthii, respectively. Patterns of amino acid frequencies of the 10-kDa genes show the distinctness of O. rufipogon and O. longistaminata from the other species. The study underscores the potential application of the prolamin genes as markers from the nuclear genome for evolutionary studies in grasses at different taxonomic levels.     

Characterization of 10 KDA prolamin genes in Phyllostachys aurea (Bambusoideae, Poaceae)

Prolamin is the dominant class of seed storage protein in grasses (Poaceae). Information on the 10 kDa multigene family coding for prolamins characteristic of the bambusoid-oryzoid grasses is limited. Two genes encoding 10 kDa prolamin were cloned and sequenced in the bambusoid species Phyllostachys aurea to assess the sequence diversity of this gene family in the oryzoid-bambusoid grasses. The genes, ~417 bp in length, were 96% similar at the DNA sequence level, differing in 12 base substitutions dispersed throughout the sequence. Eight of these mutations were nonsynonymous, leading to amino acid substitutions in the coding region, and one was nonsense, producing an amber stop codon. One gene had an open reading frame (ORF) of 139 amino acids, while the other gene had a shorter ORF (106 amino acids) due to the presence of a stop codon in the coding region and, thus, represents a pseudogene. Deduced proteins showed amino acid composition similar to that of rice. The study underscores the overall conserved nature of this multigene family and reflects considerable sequence divergence at the DNA and amino acid levels between the Oryza and the Phyllostachys genes. The systematic implication of the data is discussed in light of the inconsistent placement of Oryza in the Bambusoideae or Oryzoideae.     

CLUSTER ANALYSIS OF ANTHER-DERIVED PLANTS OF SOLANUM PHUREJA (SOLANACEAE) BASED ON MORPHOLOGICAL CHARACTERISTICS

The feasibility of grouping anther-derived plants of Solarium phureja according to ploidy based on their morphological characteristics was studied. Canonical discriminant analysis identified four characteristics (anther length, number of chloroplasts per pair of guard cells, leaf width, corolla width at widest diam) of nine measured as the most effective combination for diagnosing ploidy. Data for these characteristics from two sets of plants were subjected to two clustering techniques, one using the average linkage clustering (UPGMA of the NT-SYS programs) and the other using centroid sorting (SAS-Fastclus). Screening of anther-derived plants by cluster analysis proved to be an efficient means of separating monoploids from the other ploidy levels.     

FITNESS CONSEQUENCES OF OUTCROSSING IN A SOCIAL SPIDER WITH AN INBREEDING MATING SYSTEM

Inbreeding mating systems are uncommon because of inbreeding depression. Mating among close relatives can evolve, however, when outcrossing is constrained. Social spiders show obligatory mating among siblings. In combination with a female‐biased sex ratio, sib‐mating results in small effective populations. In such a system, high genetic homozygosity is expected, and drift may cause population divergence. We tested the effect of outcrossing in the social spider Stegodyphus dumicola. Females were mated to sib‐males, to a non‐nestmate within the population, or to a male from a distant population, and fitness traits of F1s were compared. We found reduced hatching success of broods from between‐population crosses, suggesting the presence of population divergence at a large geographical scale that may result in population incompatibility. However, a lack of a difference in offspring performance between inbred and outbred crosses indicates little genetic variation between populations, and could suggest recent colonization by a common ancestor. This is consistent with population dynamics of frequent colonizations by single sib‐mated females of common origin, and extinctions of populations after few generations. Although drift or single mutations can lead to population divergence at a relatively short time scale, it is possible that dynamic population processes homogenize these effects at longer time scales.     

'Multi-epitope-targeted' immune-specific therapy for a multiple sclerosis-like disease via engineered multi-epitope protein is superior to peptides

Antigen-induced peripheral tolerance is potentially one of the most efficient and specific therapeutic approaches for autoimmune diseases. Although highly effective in animal models, antigen-based strategies have not yet been translated into practicable human therapy, and several clinical trials using a single antigen or peptidic-epitope in multiple sclerosis (MS) yielded disappointing results. In these clinical trials, however, the apparent complexity and dynamics of the pathogenic autoimmunity associated with MS, which result from the multiplicity of potential target antigens and "epitope spread", have not been sufficiently considered. Thus, targeting pathogenic T-cells reactive against a single antigen/epitope is unlikely to be sufficient; to be effective, immunospecific therapy to MS should logically neutralize concomitantly T-cells reactive against as many major target antigens/epitopes as possible. We investigated such "multi-epitope-targeting" approach in murine experimental autoimmune encephalomyelitis (EAE) associated with a single ("classical") or multiple ("complex") anti-myelin autoreactivities, using cocktail of different encephalitogenic peptides vis-a-vis artificial multi-epitope-protein (designated Y-MSPc) encompassing rationally selected MS-relevant epitopes of five major myelin antigens, as "multi-epitope-targeting" agents. Y-MSPc was superior to peptide(s) in concomitantly downregulating pathogenic T-cells reactive against multiple myelin antigens/epitopes, via inducing more effective, longer lasting peripheral regulatory mechanisms (cytokine shift, anergy, and Foxp3+ CTLA4+ regulatory T-cells). Y-MSPc was also consistently more effective than the disease-inducing single peptide or peptide cocktail, not only in suppressing the development of "classical" or "complex EAE" or ameliorating ongoing disease, but most importantly, in reversing chronic EAE. Overall, our data emphasize that a "multi-epitope-targeting" strategy is required for effective immune-specific therapy of organ-specific autoimmune diseases associated with complex and dynamic pathogenic autoimmunity, such as MS; our data further demonstrate that the "multi-epitope-targeting" approach to therapy is optimized through specifically designed multi-epitope-proteins, rather than myelin peptide cocktails, as "multi-epitope-targeting" agents. Such artificial multi-epitope proteins can be tailored to other organ-specific autoimmune diseases.     

Impact of missing data,gene choice,and taxon sampling on phylogenetic reconstruction: the Caryophyllales (angiosperms)

Density of taxon sampling and number/kind of characters are central to achieving the ultimate goals in phylogenetic reconstruction: tree robustness and improved accuracy. In molecular phylogenetics, DNA sequence repositories such as GenBank are potential sources for expanding datasets in two dimensions, taxa and characters, to the level of “supermatrices.” However, the issue of missing characters/genomic regions is generally considered a major impediment to this endeavor. We used here the angiosperm order Caryophyllales to systematically address the impact of missing data when expanding taxon sampling and number of characters in phylogenetic reconstruction. Our analyses show that expansion of taxon sampling by ~13-fold resulted in improved phylogenetic assessment of the Caryophyllales despite up to 38% missing data. Expanding number of characters in the dataset by allowing for up to 100-fold increase in amount of missing data and inclusion of entries with about 40% missing genomic regions did not negatively impact tree structure or robustness, but to the contrary improved both. These results are timely regarding the ongoing efforts to achieve detailed assessment of the tree of life.     

High mortality and female‐biased operational sex ratio result in low encounter rates and moderate polyandry in a spider

The taxonomy of the Old World bat genus Otomops (Chiroptera: Molossidae) has been the subject of considerable debate. The failure of classical morphological studies to provide consistent patterns regarding interspecific relationships within Otomops has limited any understanding of the evolutionary history of the genus. We used traditional and geometric morphometric approaches to establish the species limits of taxa from sub‐Saharan Africa, the Arabian Peninsula, and Madagascar. Morphometric data supported the recent recognition of three distinct Afrotropical taxa: Otomops madagascariensis from Madagascar; Otomops martiensseni s.s. from southern, eastern, central, and western Africa; and an undescribed taxon from north‐east Africa and the Arabian Peninsula. Analyses of craniodental measurements and landmark‐based data showed significant cranial size and shape divergence between the three taxa. Cranial size and shape variation within Afro‐Arabian Otomops were strongly influenced by altitude, seasonality of precipitation, and precipitation in the driest month. Based on morphometric patterns and molecular divergence estimates, we suggest that morphological evolution within Afro‐Arabian Otomops occurred in response to the fluctuating climate during the Pleistocene on the one hand, and the increasing aridity and seasonality over north‐eastern Africa on the other. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, •• , ••–••.