Evolution of type C viral genes: evidence for an Asian origin of man.

Old World monkeys and apes, including man, possess, as a normal component of their cellular DNA, gene sequences (virogenes) related to the RNA of a virus isolated from baboons. A comparison of the viral gene sequences and the other cellular sequences distinguishes those Old World monkeys and apes that have evolved in Africa from those that have evolved in Asia. Among the apes, only gorilla and chimpanzee seem by these criteria to be African, whereas gibbon, orang-utan and man are identified as Asian, leading us to conclude that most of man's evolution has occurred outside Africa.     

Evolution and maintenance of cooperation via inheritance of neighborhood relationship

Cooperative behaviors are ubiquitous in nature and human society. It is very important to understand the internal mechanism of emergence and maintenance of cooperation. As we know now, the offsprings inherit not only the phenotype but also the neighborhood relationship of their parents. Some recent research results show that the interactions among individuals facilitate survival of cooperation through network reciprocity of clustering cooperators. This paper aims at introducing an inheritance mechanism of neighborhood relationship to explore the evolution of cooperation. In detail, a mathematical model is proposed to characterize the evolutionary process with the above inheritance mechanism. Theoretical analysis and numerical simulations indicate that high-level cooperation can emerge and be maintained for a wide variety of cost-to-benefit ratios, even if mutation happens during the evolving process.     

Maternal inheritance in polyploid fish inferred from mitochondrial ATPase genes analysis

The sequences of the ATPase8/6 genes for the triploid, tetraploid and pentaploid hybrids as well as for their male parent blunt snout bream were determined. In order to examine mitochondrial maternal inheritance, the sequences were subjected to a comparative sequence analysis with the homologous sequences of red crucian carp, their female parent, and zebrafish as the outgroup. Base composition and variation as well as the divergences based on nucleotide sequences and deduced amino acid sequences were calculated. Phylogenetic trees were also constructed with maximum parsimony (MP), minimum evolution (ME), neighbor joining (NJ) and the unweighted pair group method with arithmetic mean (UPGMA) algorithms in MEGA 3.1. The results showed that most nucleotide substitutions occurred at the third codon position of the two genes and thus represented synonymous mutations. The nucleotide sequence divergences of the ATPase8/6 genes ranged from 0.0% to 21.6% among ingroup samples (three types of polyploids and their parents), and 27.0–28.2% between their ingroup and the outgroup samples. All the polyploids were considerably closer in sequence relationship to the female parent red crucian carp (0.0–3.3%) compared to their male parent blunt snout bream (21.0–21.6%). The phylogenetic trees also showed a similar result. In conclusion, the mitochondrial ATPase8/6 genes of artificial polyploid fish stringently indicated maternal inheritance. Our results also suggested that the ATPase8/6 genes are valuable genetic markers to track genealogies and variations in the progenies of the hybrids.     

Endogenous viral genes are non-essential in the chicken.

DNA sequences homologous to the genomes of type C retroviruses are widespread among vertebrates. Ten genetic loci containing endogenous viral DNA sequences have been documented in the white Leghorn chicken alone. Six of these genetic loci are associated with the production of virus or of viral proteins in embryonic fibroblasts (refs 2--4, and S.M.A., L, B. Crittenden and E.G.B., in preparation) and one of the loci may be expressed in the erythroblasts of 5-day-old embryos. The abiquitous presence of endogenous viral genes among vertebrate species and the association of their expression with development of the haematopoietic system in the mouse have led to the proposal that these genes are involved in ontogeny. In addition, the genes may be implicated in oncogenesis as in the case of the AKR mouse in which a high incidence of spontaneous leukaemia is associated with the expression of endogenous murine laukaemia virus genomes. We report here the production of a fertile rooster which lacks avian leukosis virus-related endogenous viral genes and which seems to be completely normal and healthy. Thus, endogenous viral genes are apparently not essential for the normal development of the chicken. An endogenous virus-free state has also been reported for three species of jungle fowl and for the B-type viral genes of the mouse.     

Evolution of genes and genomes on the Drosophila phylogeny

Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.     

Immunodeficiency virus rev trans-activator modulates the expression of the viral regulatory genes

The pathogenic human retrovirus human immunodeficiency virus type 1 (HIV-1) encodes two trans-acting nuclear proteins, tat and rev, whose functional expression is essential for viral replication in vitro. The tat protein greatly enhances the expression of both structural and regulatory genes of HIV-1 (linked to the viral long-terminal-repeat promoter element), whereas the rev gene product (previously termed art or trs) has only been shown to be required for the synthesis of structural proteins. Here, we demonstrate that rev also moderates the expression of regulatory genes of HIV-1. It decreases the expression of messenger RNAs that encode the full-length form of the viral tat gene product or the rev protein itself, and induces the synthesis of a previously unreported, truncated tat protein. These actions of rev are mediated by a dramatic shift in the ratio of spliced to unspliced cytoplasmic HIV-1 mRNA. Therefore rev not only activates the synthesis of the viral structural proteins, but also modulates the level and quality of HIV-1 regulatory gene expression.     

Transformation of cell adhesion properties by exogenously introduced E-cadherin cDNA

E-cadherin is a cell surface glycoprotein responsible for Ca2+-dependent intercellular adhesion between epithelial cells; it is also called uvomorulin, L-CAM (ref. 3), cell-CAM 120/80 (ref.4) or Arc-1 (ref. 5). Because blocking the action of E-cadherin by monoclonal antibodies causes dispersion of compact cell colonies, this molecule is thought to be an important factor for maintenance of multicellular systems. To demonstrate directly that E-cadherin is involved in cell-cell adhesion, we cloned full-length cDNA encoding E-cadherin from F9 cells and introduced it into L fibroblasts deficient in E-cadherin. These L cells acquire strong Ca2+-dependent aggregating activity by expressing the E-cadherin derived from the introduced cDNA and were morphologically transformed so as to form colonies in which cells were tightly connected to each other.     

Evolution of the MHC class I genes of a New World primate from ancestral homologues of human non-classical genes

The products of the classical human major histocompatibility complex (MHC) class I genes (HLA-A, -B, -C) are highly polymorphic molecules that bind peptides and present them to T lymphocytes. The non-polymorphic, non-classical MHC class I gene products (HLA-E, -F, -G) are not restricting elements for the majority of T lymphocytes. The evolutionary relationship of the non-classical and classical MHC class I genes is unclear. Here we present the cloning and sequencing of the MHC class I genes of a New World primate, the cotton-top tamarin (Saguinus oedipus). The expressed MHC class I genes of this species are more closely related to the human non-classical HLA-G gene than they are to genes of the human classical HLA-A, -B, and -C loci. These observations imply that classical and non-classical genes do not necessarily constitute mutually exclusive groups over evolutionary time.     

The inheritance of PN-COOPN

An appropriate combination of COOP and Petri nets is required in order to profit from the strength of both methods. This paper gives an overview of our ongoing research on PN-COOPN, which is a paradigm and development environment for concurrent object-oriented programming based on Petri nets. We describe the object model and programming notation and emphasis the inheritance part for PN-COOPN. Supported by the Foundation of National 863 Project. Zhang Qian, born in 1973, Ph. D     

Transgene inheritance and quality improvement by expressing novel HMW glutenin subunit （HMW-GS）genes in winter wheat

The expression vector pBPC30, which carries the high molecular weight glutenin subunit (HMW-GS) 1Dx5 and 1Dy10 genes, was transferred into hexaploid winter wheat cv. Jinghua No. 1, Jing411 and Jingdong No. 6 explants of immature embryos and immature inflorescence by particle bombardment. A large number of resistant transgenic plants were obtained under the selection of herbicide bialaphos or phosphinothricin (PPT). Confirmed transgenic plants of To generation showed successful integration of HMW-GS genes and bar gene into the wheat genome. T1 generation of transgenic plants can resist 20--150 mg/L PPT.Protein analysis of T2 seed by SDS-PAGE showed that HMW-GS 1Dx5 and 1DylO genes were well expressed in offspring seed of transgenic lines by co-expression with or substitution of endogenous 1Dx2 or 1DylO. In one transgenic line, TG3-74, a new protein band between endogenous protein subunits 7 and 8 (marked as 8*) of glutenin appeared,but endogenous subunit 8 (encoded by 1By8 gene) was absent. Analysis of gluten rheological quality on seed proteins of 102 T3 plants showed that the sedimentation value of 5 transgenic lines (44.2149.0 mL) was remarkably improved,59.6%---64.3% higher than that of wild type Jinghua No. 1 and Jingdong No. 6, similar to bread wheat Cheyenne (48.0 mL). Analysis of dough rheological properties of transgenic lines showed that the dough stable time of 5 transgenic lines range from 16 to 30 min, whereas the dough stable time of wild type was only between 3--7 min. Our research suggests that introducing novel HMW-GS genes into wheat is an efficient way to improve its bread-making quality.