中国维吾尔族人群MSY1(DYF155S1)基因座多态性及其结构特点

应用荧光标记MVR-PCR、Amp-FLP与DNA序列分析技术等检测106例中国维吾尔族人群无关男性个体血纱样品,揭示了中国维吾尔族人群Y特异的小卫星MSY1 (DYF155S1)基因座5′和3′端多态性及其基因结构特点。DYF155S1基因座的多态性表现为3个方面：（1）长度多态性;（2）5′端多态性;（3）3′端多态性。106例无关个体共检出37个不同长度的片段,5′端检出68个类型,3′端检出23个类型。综合这3方面多态性,106例个体间没有相同,其基因多样性（h）超过0.9999。DNA序列分析发现该基因座5′端表现有7种模块结构,3′端有2种模块结构。DYF155S2片段缺失率约为4.7%。MVR-PCR、Amp-FLP与DNA序列分析技术结合起来可以更充分地揭示人群Y染色体特异的小卫星MSY1（DYF155S1）基因座多态性,并提出命名方式,从而为人类遗传学及法医学研究提供了有用的方法和基础资料。 Abstract:The study is to reveal the diversity and gene structure of 5′ and 3′ end of DYF155S1 locus in Y-chromosome minisatellite among Chinese Uygur population.Fluorescent MVR-PCR（minisatellite variant repeat by PCR）,Amp-FLP(Amplified fragment length polymorphism) and DNA sequencing methods were used repectively to detect 106 unrelated males among Chinese Uygur population.The polymorphisms of DYF155S1 locus could be revealed in three aspects:(1) polymorphic length:the sizes of amplified fragments ranged from 1405 to 2505bp.There are 37 types found among the 106 unrelated males.(2) polymorphism at 5′ end of DYF155S1 locus,68 types found among the 106 unrelated males.(3) polymorphism at 3′ end of DYF155S1 locus,23 types found among the 106 unrelated males.In combination of these three aspects of polymorphism,none of the 106 unrelated males tested had the same allele,and the gene diversity(h) was over 0.9999.Seven and two types of modular structure were founded in the 5′ and 3′ end of DYF155S1 locus,respectively,by DNA sequencing.The alleles at DYF155S2 locus showed yes/no dimorphism and the rate of deletion was 4.7%.The polymorphisms of DYF155S1 locus were fully revealed by using combination of MVR-PCR, Amp-FLP and DNA sequencing methods, and we suggested the nomenclature for alleles of MVR loci.These methods are useful tools and provide basic data for the study of human genetics and forensic medicine.     

European Y-chromosomal lineages in Polynesians: a contrast to the population structure revealed by mtDNA.

We have used Y-chromosomal polymorphisms to trace paternal lineages in Polynesians by use of samples previously typed for mtDNA variants. A genealogical approach utilizing hierarchical analysis of eight rare-event biallelic polymorphisms, seven microsatellite loci, and internal structural analysis of the hypervariable minisatellite, MSY1, has been used to define three major paternal-lineage clusters in Polynesians. Two of these clusters, both defined by novel MSY1 modular structures and representing 55% of the Polynesians studied, are also found in coastal Papua New Guinea. Reduced Polynesian diversity, relative to that in Melanesians, is illustrated by the presence of several examples of identical MSY1 codes and microsatellite haplotypes within these lineage clusters in Polynesians. The complete lack of Y chromosomes having the M4 base substitution in Polynesians, despite their prevalence (64%) in Melanesians, may also be a result of the multiple bottleneck events during the colonization of this region of the world. The origin of the M4 mutation has been dated by use of two independent methods based on microsatellite-haplotype and minisatellite-code diversity. Because of the wide confidence limits on the mutation rates of these loci, the M4 mutation cannot be conclusively dated relative to the colonization of Polynesia, 3,000 years ago. The other major lineage cluster found in Polynesians, defined by a base substitution at the 92R7 locus, represents 27% of the Polynesians studied and, most probably, originates in Europe. This is the first Y-chromosomal evidence of major European admixture with indigenous Polynesian populations and contrasts sharply with the picture given by mtDNA evidence.     

Low X/Y divergence in four pairs of papaya sex-linked genes

Sex chromosomes in flowering plants, in contrast to those in animals, evolved relatively recently and only a few are heteromorphic. The homomorphic sex chromosomes of papaya show features of incipient sex chromosome evolution. We investigated the features of paired X- and Y-specific bacterial artificial chromosomes (BACs), and estimated the time of divergence in four pairs of sex-linked genes. We report the results of a comparative analysis of long contiguous genomic DNA sequences between the X and hermaphrodite Y (Y(h)) chromosomes. Numerous chromosomal rearrangements were detected in the male-specific region of the Y chromosome (MSY), including inversions, deletions, insertions, duplications and translocations, showing the dynamic evolutionary process on the MSY after recombination ceased. DNA sequence expansion was documented in the two regions of the MSY, demonstrating that the cytologically homomorphic sex chromosomes are heteromorphic at the molecular level. Analysis of sequence divergence between four X and Y(h) gene pairs resulted in a estimated age of divergence of between 0.5 and 2.2 million years, supporting a recent origin of the papaya sex chromosomes. Our findings indicate that sex chromosomes did not evolve at the family level in Caricaceae, and reinforce the theory that sex chromosomes evolve at the species level in some lineages.     

用荧光标记MVR-PCR方法研究中国汉族人群DYF155S1基因座多态性

建立简便、实用的DYF155S1基因座基因分型的银染和荧光标记半自动分析方法,对中国汉族155个无关男性个体血样本DNA进行分型,两种方法分型结果一致。155人共检出66种等位基因,有38个等位基因仅出现1次。根据图谱中第一条DNA片段及DNA条带数从小至大命名,频率最高的为18和22号等位基因,其第一条DNA片段大小为180bp,DNA条带数为连续的16和17个,频率均为0.065。这一位点的基因多样性（h）为0.9789。155人中有25人表现为连续DNA谱带中有1个或2个DNA条带的丢失（mull repeat）,序列分析证明丢失的DNA条带位置对应于3型核心序列。结果表明,本文建立的分析方法能很好地揭示DYF155S1基因座5′端多态性,是目前仅作1次PCR能获得个体Y染色体多态信息较高的技术。用本方法建立的中国汉族人群DYF155S1基因座等位基因频率资料,为群体遗传学研究及法医学应用提供了基础资料。     

Role for PADI6 in securing the mRNA-MSY2 complex to the oocyte cytoplasmic lattices

The oocyte cytoplasmic lattices (CPLs) have long been predicted to function as a storage form for the maternal contribution of ribosomes to the early embryo. Our previous studies have demonstrated that ribosomal component S6 is stored in the oocyte CPLs and peptidylarginine deiminase 6 (PADI6) is critical for CPLs formation. Additionally, we found that depletion of PADI6 reduced de novo protein synthesis prior to the maternal-to-embryonic transition, therefore causing embryos to arrest at the 2-cell stage. Here, we present evidence further supporting the association of ribosomes with the CPLs by demonstrating that rRNAs are dramatically decreased in Padi6 KO oocytes. We also show that the abundance and localization of mRNAs is affected upon PADI6 depletion, suggesting that mRNAs are very possibly associated with CPLs. Consistent with this observation, the amount of the major RNA binding protein, MSY2, that is associated with the insoluble fraction of the oocytes after Triton X-100 extraction is also markedly decreased in the Padi6 KO oocytes. Furthermore, treatment of the oocytes with RNase A followed by Triton X-100 extraction severely impairs the localization of PADI6 and MSY2 in oocytes. These results indicate that mRNAs, possibly in a complex with MSY2 and PADI6, are bound in the CPLs and may play a role in securing the mRNA-MSY2 complex to the CPLs.     

Insights into Iberian population origins through the construction of highly informative Y-chromosome haplotypes using biallelic markers,STRs, and the MSY1 minisatellite

To investigate the diversity of Y chromosomes in the Iberian Peninsula and the North African population of Maghreb, we constructed superhaplotypes on the basis of 10 biallelic markers, 7 microsatellites, and 1 minisatellite located in the nonrecombining portion of the human Y chromosome. The analysis of extremely high MSY1 variability was performed by reducing the MVR-codes to modular structures. Y-STRs and MSY1 data provide information about the relationship between closely related populations such as those of Iberia. Analysis of biallelic markers allowed us to identify 7 of 12 haplogroups defined by those polymorphisms. The haplogroup background showed clear differences between Iberian populations and the North African one. The use of differently mutating Y-chromosome markers allowed us to infer different population events at different time scales: the Paleolithic background of the Iberian Peninsula, the Neolithic fingerprint on Y-chromosome lineages, and the Iron Age influence in the populations of Iberia. Implications of our results for the highly debated origin of Basques are also discussed.     

CDC2A (CDK1)-mediated phosphorylation of MSY2 triggers maternal mRNA degradation during mouse oocyte maturation

Degradation of maternal mRNA is thought to be essential to undergo the maternal-to-embryonic transition. Messenger RNA is extremely stable during oocyte growth in mouse and MSY2, an abundant germ cell-specific RNA-binding protein, likely serves as a mediator of global mRNA stability. Oocyte maturation, however, triggers an abrupt transition in which most mRNAs are significantly degraded. We report that CDC2A (CDK1)-mediated phosphorylation of MSY2 triggers this transition. Injecting Cdc2a mRNA, which activates CDC2A, overcomes milrinone-mediated inhibition of oocyte maturation, induces MSY2 phosphorylation and the maturation-associated degradation of mRNAs. Inhibiting CDC2A following its activation with roscovitine inhibits MSY2 phosphorylation and prevents mRNA degradation. Expressing non-phosphorylatable dominant-negative forms of MSY2 inhibits the maturation-associated decrease in mRNAs, whereas expressing constitutively active forms induces mRNA degradation in the absence of maturation and phosphorylation of endogenous MSY2. A positive-feedback loop of CDK1-mediated phosphorylation of MSY2 that leads to degradation of Msy2 mRNA that in turn leads to a decrease in MSY2 protein may ensure that the transition is irreversible.     

东海大陆架虾类资源量评估

根据2008年春(5月)、夏(8月)、秋(11月)、冬(2009年2月)四季东海区桁杆拖虾网调查资料, 应用资源密度法首次估算了调查海域主要经济虾类和总体的现存资源量和最大持续产量(MSY)。结果表明: 调查海域虾类季度平均资源密度为203.5 kg/km2。根据季节分布, 以夏季最高, 冬季最低; 根据区域分布, 南部海域最高, 中部最低。调查海域虾类的现存资源量约为10.6×104 t, MSY约为22.2×104 t, 与2008年调查海域虾类渔获量比较, 表明该海域虾类资源总体利用略显不足, 尚有一定潜力。在主要经济虾类的现存资源量与MSY中, 以假长缝拟对虾Parapenaeus fissuroides最高; 与历史资料相比, 某些经济价值较高的种类, 如哈氏仿对虾Parapenaeopsis hardwickii、日本对虾Penaeus japonicus等的资源量明显减少, 而长角赤虾Metapenaeopsis longirostris等经济虾类较低的种类资源量有所上升, 这说明东海大陆架海域虾类资源组成情况已经发生了很大改变。       

非Allee哺乳种群系统的最大持续生产量

通过计算和模拟发现：(1)对于给定的净生殖率,非Allee种群系统的最大持续生产量随系统的形状参数的增大而减少;(2)对于给定的形状参数。非Allee种群系统的最大持续生产量随系统的净生殖率的增大而增大。