Cross-species chromosome painting unveils cytogenetic signatures for the Eulipotyphla and evidence for the polyphyly of Insectivora

Insectivore-like animals are traditionally believed among the first eutherian mammals that have appeared on the earth. The modern insectivores are thus crucial for understanding the systematics and phylogeny of eutherian mammals as a whole. Here cross-spe

Features and trend of loss of promoter-associated CpG islands in the human and mouse genomes

CpG islands (CGIs) are often considered as gene markers, but the number of CGIs varies among mammalian genomes that have similar numbers of genes. In this study, we investigated the distribution of CGIs in the promoter regions of 3,197 human-mouse ortholo

Origination and evolution of a human-specific transmembrane protein gene, c1orf37-dup

A transmembrane protein gene, c1orf37-dup, was identified as a young gene specific to humans. It was derived from the conserved c1orf37 gene through retroposition after the divergence of human and chimpanzee. This gene has evolved rapidly driven by positi

Origin and evolution of new exons in rodents

Gene number difference among organisms demonstrates that new gene origination is a fundamental biological process in evolution. Exon shuffling has been universally observed in the formation of new genes. Yet to be learned are the ways new exons originate and evolve, and how often new exons appear. To address these questions, we identified 2695 newly evolved exons in the mouse and rat by comparing the expressed sequences of 12,419 orthologous genes between human and mouse, using 743,856 pig ESTs as the outgroup. The new exon origination rate is about 2.71 x 10(-3) per gene per million years. These new exons have markedly accelerated rates both of nonsynonymous substitutions and of insertions/ deletions (indels). A much higher proportion of new exons have Kappa(a)/Kappa(s) ratios > 1 (where K-a is the nonsynonymous substitution rate and K-s is the synonymous substitution rate) than K do the old exons shared by human and mouse, implying a role of positive selection in the rapid evolution. The majority of these new exons have sequences unique in the genome, suggesting that most new exons might originate through "exonization" of intronic sequences. Most of the new exons appear to be alternative exons that are expressed at low levels.

A morphologically variant natural population of cyprinids without dorsal fin possibly derived from Mystacoleucus marginatus (Osteichthyes: Teleostes) from the Lancang Jiang River, Yunnan, China

In July 2001, 15 grotesque cyprinid specimens were collected in the Lancangjiang River (of the upper reaches of the Mekong River) in Menglun Town, Xishuanbanna Prefecture, Yunnan Province, PR China. These specimens are characterized by surprising characte

云南青jiang鱼类的分类和分布(jiang形目:青jiang科)

记录了采自云南的青jiang属1新亚种及1新纪录种。中华青jiang, 新亚种O. latipes sinensis subsp. nov.与日本青jiang指名亚种O. latipes的主要区别: 新亚种第一肋骨连接第二脊椎骨上, 平均脊椎数为29.2±0.6, 胸鳍条多数为9, 染色体为2n=46。小青jiangO. minutillus新纪录种, 分布于西双版纳。还报导了青jiang属的地理分布, 介绍了属的特征。新种模式标本存中国科学院昆明动物研究所鱼类标本室。图3表2参5

Evaluation of Clonorchis sinensis recombinant 7-kilodalton antigen for serodiagnosis of clonorchiasis

The diagnostic applicability of the Clonorchis sinensis recombinant 7-kDa protein was evaluated. In enzyme-linked immunosorbent assays and immunoblots, the protein showed high sensitivities (81.3 and 71.9%, respectively) and specificities (92.6 and 89.7%, respectively) for sera obtained from various helminthic infections. Some paragonimiasis sera showed cross-reactions. The antigen might be valuable in the serodiagnosis of human clonorchiasis.

Direct detection of the relative strength of Rashba and Dresselhaus spin-orbit interaction: Utilizing the SU(2) symmetry

We propose a simple method to detect the relative strength of Rashba and Dresselhaus spin-orbit interactions in quantum wells (QWs) without relying on the directional-dependent physical quantities. This method utilizes the two different critical gate voltages that leading to the remarkable signals of SU(2) symmetry, which happens to reflect the intrinsic-structure-inversion asymmetry of the QW. We support our proposal by the numerical calculation of in-plane relaxation times based on the self-consistent eight-band Kane model. We find that the two different critical gate voltages leading to the maximum spin-relaxation times [one effect of the SU(2) symmetry] can simply determine the ratio of the coefficients of Rashba and Dresselhaus terms. Our proposal can also be generalized to extract the relative strengths of the spin-orbit interactions in quantum-wire and quantum-dot structures.

Raman and infrared properties and layer dependence of the phonon dispersions in multilayered graphene

The symmetry group analysis is applied to classify the phonon modes of N-stacked graphene layers (NSGLs) with AB and AA stacking, particularly their infrared and Raman properties. The dispersions of various phonon modes are calculated in a multilayer vibrational model, which is generalized from the lattice vibrational potentials of graphene to including the interlayer interactions in NSGLs. The experimentally reported redshift phenomena in the layer-number dependence of the intralayer optical C-C stretching mode frequencies are interpreted. An interesting low-frequency interlayer optical mode is revealed to be Raman or infrared active in even or odd NSGLs, respectively. Its frequency shift is sensitive to the layer number and saturated at about 10 layers.

A lattice dynamical treatment for the total potential energy of single-walled carbon nanotubes and its applications: relaxed equilibrium structure, elastic properties, and vibrational modes of ultra-narrow tubes

In this paper, we propose a lattice dynamic treatment for the total potential energy of single-walled carbon nanotubes (SWCNTs) which is, apart from a parameter for the nonlinear effects, extracted from the vibrational energy of the planar graphene sheet. The energetics, elasticity and lattice dynamics are treated in terms of the same set of force constants, independently of the tube structures. Based upon this proposal, we have investigated systematically the relaxed lattice configuration for narrow SWCNTs, the strain energy, the Young's modulus and Poisson ratio, and the lattice vibrational properties with respect to the relaxed equilibrium tubule structure. Our calculated results for various physical quantities are nicely in consistency with existing experimental measurements. In particular, we verified that the relaxation effect makes the bond length longer and the frequencies of various optical vibrational modes softer. Our calculation provides evidence that the Young's modulus of an armchair tube exceeds that of the planar graphene sheet, and that the large diameter limits of the Young's modulus and Poisson ratio are in agreement with the experimental values of graphite; the calculated radial breathing modes for ultra-narrow tubes with diameters ranging between 2 and 5 angstrom coincide with the experimental results and the existing ab initio calculations with satisfaction. For narrow tubes with a diameter of 20 angstrom, the calculated frequencies of optical modes in the tubule's tangential plane, as well as those of radial breathing modes, are also in good agreement with the experimental measurements. In addition, our calculation shows that various physical quantities of relaxed SWCNTs can actually be expanded in terms of the chiral angle defined for the corresponding ideal SWCNTs.

A full spd tight-binding treatment for electronic bands of graphitic tubes

A tight-binding (TB) treatment with the inclusion of d orbitals is applied to the electronic structures of graphitic tubes. The results show that the high angular moment bases in TB scheme are necessary to account the severe curvature effect in ultra-thin single wall carbon nanotubes, especially for properly reproducing the band edge overlap behavior in (5, 0) tube, predicted by the existing ab initio calculations. In the large diameter limit, the participation of two synnmetry-allowed d bases provides a natural replication to the recent measured electronic dispersions of valence band of graphene when the strong anisotropy due to the two-dimensional planar hexagonal sheet structure is dealt with properly. In addition, the detailed relation between the two sets of quantum numbers of screw symmetry and that of zone folding is formulated in appendix. (C) 2008 Elsevier Ltd. All rights reserved.