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Pyropia haitanensis (Bangiales, Rhodophyta) ((T.J. Chang et B.F. Zheng) N. Kikuchi et M. Miyata) is a unique cultivar in China and the main problem with its cultivation lies in a lack of effective technology to distinguish intraspecific strains. In this study, we firstly obtained the complete sequence of rDNA of Pyropia haitanensis in China, which can help identify intraspecific variation within this species. The whole unit is composed of a small-subunit (SSU) rRNA gene with a full length of 2953 base pairs (bp) with two classes of introns and an exon sequence of 1837 bp; moreover, the complete sequence of the large-subunit (LSU) rRNA gene (length 4444 bp) also contains two introns; the length of the 5.8S rRNA gene is 158 bp; the length of internal transcribed spacers 1 (ITS1) is 334 bp and that of ITS2 is 678 bp; and the complete sequence of intergenic spacer (IGS) is 6969 bp. Some portions of the IGS sequences were used to analyze the similarities among five strains of Pyropia haitanensis; the sequence ranged from 4264 bp to 4273 bp and the G + C content was 53%. We also found 118 variable sites in the IGS which account for approximately 2.8% of the whole length. In conclusion, the nuclear ribosomal DNA sequence turned out to be an effective molecular marker for the taxonomic identification of Pyropia haitanensis. [ABSTRACT FROM AUTHOR]

Initial progress in the science of ‘genetics’ in the first half of the 20th century was mainly driven by studies utilizing mutations and consequent changes in phenotype. The structural and functional nature of the gene was far from being understood. That state of understanding started changing from the 1940s. In the following decades, with the discovery of the double helix followed by the discoveries on gene structure and expression, there was a period when the structural and functional aspects of the gene could be conceived in terms of one entity, the cistron. However, the discovery of intervening sequences caused this unified concept to fall apart, making the gene concept a subject of philosophical debate again. Meanwhile, over time, technological progress in molecular biology had the field forge ahead rapidly, ultimately leading to the sequencing of the human genome and genomes of other species, and giving birth to the science of genomics. Developments in genomics have given rise to certain applied sub-disciplines like pharmacogenomics and toxicogenomics. While the full potential of pharmaco- and toxicogenomics is yet to be harnessed, they nevertheless have had an impact in drug development and safety assessment, such that the future promise of genomics seems achievable. At present, it is a good opportunity to revisit the path from the development of the initial gene concept and the philosophical debate surrounding the meaning of the term ‘gene’ to the current state of understanding of genes and genomes and their role in health and disease. [ABSTRACT FROM AUTHOR]

The chloroplast NAD(P)H dehydrogenase complex, a homologue of mitochondrial complex I, consists of >15 subunits, of which 11 are encoded by the chloroplast genome (ndhA-K). The ndhC and ndhK genes are partially overlapped and cotranscribed in many land plants. The downstream ndhK mRNA possesses 4 possible AUG initiation codons in many dicot plants. By using an efficient in vitro translation system from tobacco chloroplasts, we defined that the major initiation site of tobacco ndhK mRNA5 is the third AUG that is located 4 nt upstream from the ndhCstop codon. Mutation of the ndhC stop codon (UAG) arrested translation of the ndhK cistron. Frameshift of the ndhC coding strand inhibited also translation of the distal cistron. The results indicated that ndhK translation depends on termination of the preceding cistron, namely transla- tional coupling. Surprisingly, removal of the ndhC 5'-UTR and its AUG still supported substantial translation of the ndhK cistron. This translation was abolished again by removing the ndhC stop codon. Although translation of the downstream cistron of an overlapping mRNA is generally very low, we found that the ndhCIK mRNA produces NdhK and NdhC in similar amounts. Based on subunit compositions of the bacterial complex I, the stoichiometry of NdhK and NdhC is suggested to be 1:1 in chloroplasts. To meet this stoichiometry, the ndhC/K mRNA is translated not only by a translational coupling event but also by a termination codon- dependent pathway. [ABSTRACT FROM AUTHOR]

Through summarizing the evolution of corporate gene theory,the paper finds out that in the current research full attention has not yet been paid to the significance of the dividable feature of gene. Then, by using the cistron theory of gene, we build a new cistron systematic model of corporate gene, which is a three-level systematic structure including an internal fine structure of corporate gene (i. e. the belief-awareness base pair controlling corporate spirit and the resource-capacity base pair controlling the corporate body), a corporate routine as a corporate gene itself, and corporate values explicit mechanism as a corporate genetic carrier. The completion and systematization of the said systematic structure offer obvious instructive meaning to the process of firm growth and transformation. The application of the model in corporate transformation involves the cistron genetic systematic model of corporate transformation based on the cistron systematic model of corporate gene and the cistron genetic strategy and operation in two major forms of corporate transformation. In this way of application, we demonstrate the practical significance and theoretical value of the new cistron systematic model of corporate gene. [ABSTRACT FROM AUTHOR]

Helper component-proteinase (HC-Pro) of Wheat streak mosaic virus strain Sidney 81 (WSMV-Sidney 81) was systematically replaced with the corresponding cistron derived from four strains of WSMV (Type, TK1, CZ, and El Batán 3), the tritimovirus Oat necrotic mottle virus (ONMV), the rymoviruses Agropyron mosaic virus (AgMV) and Hordeum mosaic virus (HoMV), or the potyviruses Tobacco etch virus (TEV) and Turnip mosaic virus (TuMV). These HC-Pro proteins varied in amino acid sequence identity shared with HC-Pro of WSMV-Sidney 81 from high (strains of WSMV at ∼86–99%) to moderate (ONMV at 70%) to low (rymoviruses and potyviruses at ∼15–17%). Surprisingly, all chimeric viral genomes examined were capable of systemic infection of wheat upon inoculation with RNA transcripts produced in vitro. HC-Pro replacements derived from tritimoviruses did not alter host range relative to WSMV-Sidney 81, as each of these chimeric viruses was able to systemically infect wheat, oat, and corn line SDp2. These results indicate that differences in host range among tritimoviruses, including the inability of ONMV to infect wheat or the inability of WSMV strains Type and El Batán 3 to infect SDp2 corn, are not determined by HC-Pro. In contrast, all chimeric viruses bearing HC-Pro replacements derived from rymoviruses or potyviruses were unable to infect SDp2 corn and oat. Collectively, these results indicate that HC-Pro from distantly related virus species of the family Potyviridae are competent to provide WSMV-Sidney 81 with all functions necessary for infection of a permissive host (wheat) and that virus–host interactions required for systemic infection of oat and SDp2 corn are more stringent. Changes in symptom severity or mechanical transmission efficiency observed for some chimeric viruses further suggest that HC-Pro affects virulence in WSMV. [Copyright &y& Elsevier]

There is considerable evidence suggesting that the switch from γ to δ and β chain production after birth is due, in part, to silencing of the γ genes by stage-specific factors which bind to their promoters and to the competition from the adult (δ and β) genes for a common enhancer element located in the locus control region. As a consequence one can expect that the increased Hb F production in adults with hereditary persistence of fetal hemoglobin or δβ-thalassemia is directed mainly by γ-globin genes in cis to the deletion(s) responsible for these conditions. Here we review data on heterozygotes with γ-, δ-, or δβ-thalassemia, who also had anγ mutation, in cis or in trans, which was used as a marker of γ gene expression. The results show that a deletion affecting adult β genes favors the expression of γ genes in cis, while the deletion of a single γ gene does not affect the expression of the β gene in cis but leads to a faster γ→β switch postnatally. [ABSTRACT FROM AUTHOR]

The ratio of DNA divergence to cistron divergence was estimated for various comparisons of Drosophila and mammalian species. It was shown that a negative correlation exists between this ratio and the length of one generation. It was proposed that the majority of the amino acid substitutions in evolution are the result of random fixation of nearly neutral mutations for which selection intensity fluctuates considerably but the average selection coefficient is very slightly negative. On the other hand, the evolutionary rate of DNA divergence is negatively correlated with the generation time if the majority of mutations are completely neutral and if mutation rate at the nucleotide level is mildly dependent on the generation time. [ABSTRACT FROM AUTHOR]