Global distribution of Y-chromosome haplogroup C reveals the prehistoric migration routes of African exodus and early settlement in East Asia

The regional distribution of an ancient Y-chromosome haplogroup C-M130 (Hg C) in Asia provides an ideal tool of dissecting prehistoric migration events. We identified 465 Hg C individuals out of 4284 males from 140 East and Southeast Asian populations. We genotyped these Hg C individuals using 12 Y-chromosome biallelic markers and 8 commonly used Y-short tandem repeats (Y-STRs), and performed phylogeographic analysis in combination with the published data. The results show that most of the Hg C subhaplogroups have distinct geographical distribution and have undergone long-time isolation, although Hg C individuals are distributed widely across Eurasia. Furthermore, a general south-to-north and east-to-west cline of Y-STR diversity is observed with the highest diversity in Southeast Asia. The phylogeographic distribution pattern of Hg C supports a single coastal 'Out-of-Africa' route by way of the Indian subcontinent, which eventually led to the early settlement of modern humans in mainland Southeast Asia. The northward expansion of Hg C in East Asia started similar to 40 thousand of years ago (KYA) along the coastline of mainland China and reached Siberia similar to 15 KYA and finally made its way to the Americas. Journal of Human Genetics (2010) 55, 428-435; doi:10.1038/jhg.2010.40; published online 7 May 2010

On diagonal-Schur complements of block diagonally dominant matrices

It is known that the diagonal-Schur complements of strictly diagonally dominant matrices are strictly diagonally dominant matrices [J.Z. Liu, Y.Q. Huang, Some properties on Schur complements of H-matrices and diagonally dominant matrices, Linear Algebra Appl. 389 (2004) 365-380], and the same is true for nonsingular H-matrices [J.Z. Liu, J.C. Li, Z.T. Huang, X. Kong, Some properties of Schur complements and diagonal-Schur complements of diagonally dominant matrices, Linear Algebra Appl. 428 (2008) 1009-1030]. In this paper, we research the properties on diagonal-Schur complements of block diagonally dominant matrices and prove that the diagonal-Schur complements of block strictly diagonally dominant matrices are block strictly diagonally dominant matrices, and the same holds for generalized block strictly diagonally dominant matrices. (C) 2010 Elsevier Inc. All rights reserved.

山羊品种间线粒体DNA限制性片段长度多态性研究

该试验利用 Apal，BamHI，BclI，BglI，BglⅡ，DraI，EcoRI，EcoRV，HaeⅡ，HindⅢ, KpnI，PstI，PvuⅡ，SacI，SalI，SmaI 和 X hoI 计18种限制性内切酶, 研究了来自欧洲、非洲及国内的5个山羊品种共计33只个体的 mtDNA, 共检测出27种限制性态型，可归结为8种单倍型. 结果表明, 国内2个山羊品种的基本单倍型为 BamHl-A, Bcl, I-B, ClaI-A, EcoRI-A, EcoRV- A, HaeIIA, HindIII-C和PvuⅡ-A, 以及为 BamHl-A,BcII-A,ClaI-A, EcoRI-A, EcoRV-A, HaeⅡ-A, HindIII-C和PvuⅡ-A.II一A, 而欧洲及非洲3个山羊品种基本的单倍型为BamHl-B, BcII-A, ClaI-A, EcoRI-A, EcoRV-A, HaeⅡ-A, HindIII-B和PvuⅡ-A，这一结果提示本研究几个受试山羊品种可能有两种不同的母系来源; 同时, 各品种的分子聚类图也表明国内2个山羊品种间具有较近的亲缘关系, 而欧洲品种和非洲3个品种间的亲缘关系较近, 这一结果也支持上述几个受试山羊品种可能有不同野生祖先的结论, 同时也验证了欧洲品种萨能羊曾引入过奴比羊的事实。

Protein three-dimensional structural databases: Domains, structurally aligned homologues and superfamilies

This paper reports the availability of a database of protein structural domains (DDBASE), an alignment database of homologous proteins (HOMSTRAD) and a database of structurally aligned superfamilies (CAMPASS) on the World Wide Web (WWW). DDBASE contains information on the organization of structural domains and their boundaries; it includes only one representative domain from each of the homologous families. This database has been derived by identifying the presence of structural domains in proteins on the basis of inter-secondary structural distances using the program DIAL [Sowdhamini & Blundell (1995), Protein Sci. 4, 506-520]. The alignment of proteins in superfamilies has been performed on the basis of the structural features and relationships of individual residues using the program COMPARER [Sali & Blundell (1990), J. Mol. Biol. 212, 403-428]. The alignment databases contain information on the conserved structural features in homologous proteins and those belonging to superfamilies. Available data include the sequence alignments in structure-annotated formats and the provision for viewing superposed structures of proteins using a graphical interface. Such information, which is freely accessible on the WWW, should be of value to crystallographers in the comparison of newly determined protein structures with previously identified protein domains or existing families.