东亚人群 LMBR1 基因 Intron 5的遗传多样性研究

人LMBR1(Limb region 1 homolog (mouse)) 基因位于染色体7q36区域，全长约210.2 kb，含17个外显子，编码一个由490个氨基酸构成的跨膜蛋白。研究表明，LMBR1 基因的表达活性与脊椎动物四肢的手指或脚趾数目变化有关；另外，发生在其重要元件——intron 5 内的许多变异与多种表型的轴前多指症((PPD, Preaxial polydactyly)存在相关性，这主要是因为LMBR1 intron 5 内含有一个与骨骼系统发育有关的基因（SHH(Sonic hedgehog)基因）的远程顺式调控元件。本研究旨在探究LMBR1基因 intron 5 内的遗传多样性，进而评估HapMap计划的样本选择策略，并检测该区域是否受自然选择的作用。 国际人类基因组单体型图计划(HapMap Project，The International Haplotype Map Project) 于2002年10月正式启动，该计划旨在构建人类基因组中常见变异的遗传图式。自其数据发布以来，广泛应用于生物医学、群体遗传学等领域，在复杂疾病的遗传机理研究、自然选择的检测等方面做出了前所未有的贡献；但是HapMap计划中样本的代表性有待评估。 本研究中，我们综合考虑地理来源信息及线粒体单倍型类群 (Haplogroup)信息选择了41个东亚人作为样本（以保证样本的代表性），测定位于LMBR1 基因intron 5 内的目的片段中存在的单核苷酸多态性(SNP, Singe nucleotide polymorphism)位点，通过所得数据与HapMap数据的比较，发现二者之间差异显著且HapMap数据不能覆盖所有我们得到的常见变异，因而我们认为：HapMap计划中国部分的样本选择策略有待进一步完善。 关于自然选择的研究不仅可以使我们了解生物的进化机制，同时还对复杂疾病的遗传机理研究具有重要的提示作用，因而，对于自然选择的检测，一直以来都是生物学研究的重点。平衡选择是一种维持遗传多态性的自然选择方式，现已发现很多与特定疾病或性状相关的基因或调控序列受平衡选择的作用，如 G6PD 基因、PTC 基因、FMO3 基因、FSHB 基因及 CCR5 基因5’端顺式调控区等我们对41个东亚样本中LMBR1 intron 5 内一段长为9256 bp (Chr7: 156280954-156271699 (Build36))的序列进行以 Tajima’s D 检验为主的群体遗传学分析，发现该区域在进化历程中受到平衡选择的作用。LMBR1 intron 5 内的多态位点与多种表型的多指症存在相关性，受其调控的 SHH 基因在骨骼系统发育中具有重要作用，人类骨骼系统的适应性进化等三方面的因素为该区域受平衡选择的作用提供了进一步的佐证。 总之，本研究对HapMap计划的样本选择策略和数据应用提供了一定的参考；同时还发现一个与骨骼系统发育有关的基因调控元件受平衡选择的作用。

长白山森林生态系统中的稀有和濒危多孔菌

In last 10 years,extensive field inventories were carried out to investigate Polypore species, the major wood decaying fungi in the Changbaishan Nature Reserve of Northeastern China. The following 27 species were treated as rare or threathened species: Amylocystis lapponica (Romell) Singer, Anomoporia albolutescens (Romell) Pouzar, Anomoporia bombycina (Fr.) Pouzar, Anomoporia vesiculosa Y.C. Dai & Niemel, Antrodia carbonica (Overh.) Ryvarden & Gilb., Antrodia crassa (P. Karst.) Ryvarden, Antrodiella citrinella Niemel & Ryvarden, Diplomitoporus flavescens (Bres.) Dománski, Donkioporia expansa (Desm.) Kotl. & Pouzar, Gloeophyllum carbonarium (Berk. & M.A. Curtis) Ryvarden, Haploporus odorus (Sommerf.) Bondartsev & Singer, Inonotopsis subiculosa (Peck) Parmasto, Nigroporus ussuriensis (Bondartsev & Ljub.) Y.C. Dai & Niemela, Oxyporus sinensis X.L. Zeng, Parmastomyces taxi (Bondartsev) Y.C. Dai & Niemela, Phellinidium sulphurascens (Pilat) Y.C. Dai, Phellinus vaninii Ljub., Polyporus vassilievae Thorn, Pycnoporellus fulgens (Fr.) Donk, Skeletocutis brevispora Niemela, Skeletocutis ochroalba Niemela, Skeletocutis perennis Ryvarden, Trechispora candidissima (Schwein.) Bondartsev & Singer, Wolfiporia dilatohypha Ryvarden & Gilb., Wolfiporia curvispora Y.C. Dai, Wrightoporia avellanea (Bres.) Pouzar and Wrightoporia lenta (Oveh. & J. Lowe) Pouzar. Polypores are richer in East Asia than in Europe and North America, not only because of destructive galciations and fewer hosts in the latters, but also because of the geography. NE Asia is a link between Europe and North America. Changbaishan Nature Reserve is very rich in polypores, and over 260 species were recorded in the reserve. Some rare species in North America and Europe, for instance, Anomoporia albolutescens, Antrodia crassa, Diplomitoporus flavescens, Inonotopsis subiculosa and Skeletocutis ochroalba etc. were found in Changbaishan Nature Reserve as well, and these species are in fact rare in the earth. Most of the 27 species occurred on fallen trunks or rotten wood in the reserve, but some of them grew on living trees. 18 species occured on substrate of gymnosperms, and 9 species grew on wood of angiosperm.Among the 27 species, 7 species caused a brown rot,and 20 species produced a white rot. The morphology, substrate and ecology of each species were briefly discussed. The most important tool for polypore conservation is the conservation of their habitats, and it is necessary to study the ecology of the rare and threathened species of polypores in the Changbaishan Nature Reserve. Because most of polypores live on the substrate of fallen trunks and rotten wood, it is very important to keep such substrate in the ecosystem.

Isolation and characterization of microsatellite loci from mangrove red snapper Lutjanus argentimaculatus

Lutjanus argentimaculatus, also called mangrove red snapper, is a commercially important fish in East Asia. A proper understanding of population structure is primarily linked with the management of genetic resources in exploiting marine fisheries. Herein, seven microsatellite loci, which showed high polymorphism (observed heterozygosity per locus ranging from 0.3571 to 0.7857 and expected heterozygosity per locus ranging from 0.6236 to 0.8821), were isolated and characterized from L. argentimaculatus. Cross-species amplifications also indicate that primers designed for these loci may be useful for further studies about other closely phylogenetic species of the family Lutjanidae.

Cultivation of the brown alga Hizikia fusiformis (Harvey) Okamura: enhanced seedling production in tumbled culture

The reuse of holdfasts for regeneration of young seedlings or using wild juvenile plants as the seedling source has played the major role in commercial cultivation of the brown alga Hizikia fusiformis in East Asia over the past 20 years. The possibility of employing zygote-derived germlings for producing seedlings has been discussed in the literature, but has not yet become a reality. Three main obstacles have limited the use of zygotes as a main source of seedlings, (1) the dioecious nature of the algal life cycle which may lead to asynchronous male and female receptacle development and thus different timing of egg and spermatozoa expulsion, (2) the low attachment rate when using zygote-derived germlings with developed rhizoids from wild parental plants for seeding production, and (3) the problem of culturing young germlings in regions where water temperature is high in summer. In this investigation, shifting the timing of receptacle formation earlier than in nature was performed by tumbling the algae in a long-day tank (16-h light per day). Synchronization of egg and spermatozoa expulsion and thereafter fertilization were conducted in indoor tanks. Receptacle formation in constant long days could be shifted by 20 days earlier than in plants cultured on long lines in the open sea, or I month earlier than in plants growing on intertidal rocks. Synchronized expulsion of eggs and spermatozoon led to a high rate of fertilization. This was achieved by tumbling the male and female receptacle-bearing branchlets in the same tank at low density in high irradiance. In two independent trials, a total of 1,400,000 zygote-derived germlings were obtained from 620 g (fresh weight) female sporophytes. The germlings shed from the receptacles were at an identical developmental stage indicating high synchronization of expulsion of eggs and spermatozoon followed by fertilization. Approximately 63% ( +/-9.6%) of the germlings were shed from the receptacle between 16 and 24 It after fertilization and 20% ( +/-11.9%) remained on the receptacle for 3 days after fertilization. Germlings were seeded on string collectors before rhizoids started to elongate and the attachment efficiency was enhanced. Young seedlings reached 800 ( +/-50) mum in length in 25 days at 25 degreesC before they were transferred to open sea cultivation. These results provide the basis of a practical way of seedling production by use of zygote-derived germlings in the commercial cultivation of Hizikia fusiformis. (C) 2004 Elsevier B.V All rights reserved.

Cultivation of the brown alga Hizikia fusiformis (Harvey) Okamura: controlled fertilization and early development of seedlings in raceway tanks in ambient light and temperature

Commercial cultivation of the dioecious brown macroalga Hizikia fusiformis (Harvey) Okamura in East Asia depends on the supply of young seedlings from regenerated holdfasts or from wild population. Recent development of synchronized release of male and female gametes in tumble culture provides a possibility of mass production of young seedlings via sexual reproduction. In this paper, we demonstrate that controlled fertilization can be efficiently realized in ambient light and temperature in a specially designed raceway tank in which the sperm-containing water has been recirculated. The effective fertilization time of eggs by sperm was found to be within six hours. Fast growth and development of the young seedlings relied on the presence of water currents. Velocity tests demonstrated that young seedlings of 2-3 mm in length could withstand a water current of 190 cm s(-1) stop without detachment. Culture experiments at 24 h postfertilization showed that elongation of both the seedlings and their rhizoids were not hampered by high irradiance up to 600 mu mol photons m(-2) stop s(-1) stop. However, growth was slightly retarded if cultured at a temperature of 16 degrees C compared to other culture temperatures of 22, 25 and 29 degrees C. No seedling detachment was observed after transfer of the young seedlings to raft cultivation in the sea after one and 1.5 months post-fertilization, indicating the feasibility of obtaining large quantity of seedlings in such a system.

REE and epsilon(Nd) of clay fractions in sediments from the eastern Pacific Ocean: Evidence for clay sources

Clay fractions in the non-calcareous surface sediments from the eastern Pacific were analyzed for clay minerals, REE and Nd-143/Nd-144. Montmorillonite/illite ratio (M/I ratio), total REE contents (Sigma REE), LREE/HREE ratio and cerium anomaly (delta Ce) may effectively indicate the genesis of clay minerals. Clay fractions with M/I ratio > 1, delta Ce < 0.85, Sigma REE > 400 mu g/g, LREE/HREE ratio approximate to 4, and REE patterns similar to those of pelagic sediments are terrigenous and autogenetic mixed clay fractions and contain more autogenetic montmorillonite. Clay fractions with M/I ratio < 1, delta Ce=0.86 to 1.5, Sigma REE=200 to 350 mu g/g, LREE/HREE ratio approximate to 6 and REE distribution patterns similar to that of China loess are identified as terrigenous clay fraction. The Nd-143/Nd-144 ratios or epsilon(Nd) values of clay fractions inherit the features of terrigenous sources of clay minerals. Clay fractions are divided into 4 types according to epsilon(Nd) values. Terrigenous clay minerals of type I with the eNd values of -8 to -6 originate mainly from North American fluvial deposits. Those of type 11 with the epsilon(Nd) Values of -9 to -7 are mainly from the East Asia and North American fluvial deposits. Those of type III with epsilon(Nd) values of -6 to -3 could come from the central and eastern Pacific volcanic islands. Those of type IV with epsilon(Nd) values of -13 to -12 may be from East Asia eolian. The terrigenous and autogenetic mixed clay fractions show patchy distributions, indicating that there are volcanic or hot-spot activities in the eastern Pacific plate, while the terrigenous clay fractions cover a large part of the study area, proving that the terrigenous clay minerals are dominant in the eastern Pacific.

The paleoclimatic events and cause in the Okinawa Trough during 50 kaBP

Planktonic foraminiferal delta O-18 record for core DGKS9603 from the Okinawa Trough shows a series of climatic fluctuations and sudden cooling events in short time scale during 50 kaBP, which appear to correlate closely to the Younger Dryas and Heinrich events H1-5 recorded in Chinese loess, the South China Sea, the North Atlantic cores and the Greenland ice cores. Three polarity reversal events, correlating to Gothenburg, Mungo and Laschamp events, approximately correspond to Heinrich events H1, H3 and H5 respectively, which could be a cause of global climate changes. The delta O-18 curve of the Okinawa Trough is well associated with the grain size record of the Lijiayuan loess profile in northwestern China and is somewhat different from the climate fluctuations documented in the Greenland ice cores. These correlation results indicate that regional factors play an important role in controlling the climate changes in the East Asia, and the East Asian Monsoon could be the prominent regional controlling factor.

Paleoenvironmental change in the middle Okinawa Trough since the last deglaciation: Evidence from the sedimentation rate and planktonic foraminiferal record

Well-dated, high-resolution records of planktonic foraminifera and oxygen isotopes from two sediment cores, A7 and E017, in the middle Okinawa Trough reveal strong and rapid millennial-scale climate changes since similar to 18 to 17 thousand years before present (kyr B.P.). Sedimentation rate shows a sudden drop at similar to 11.2 cal. kyr B.P. due to a rapid rise of sea level after the Younger Dryas (YD) and consequently submergence of the large continental shelf on the East China Sea (ECS) and the retreat of the estuary providing sediment to the basin. During the last deglaciation, the relative abundance of warm and cold species of planktonic foraminifera fluctuates strongly, consistent with the timing of sea surface temperature (SST) variations determined from Mg/Ca measurements of planktonic foraminifera from one of the two cores. These fluctuations are coeval with climate variation recorded in the Greenland ice cores and North Atlantic sediments, namely Heinrich event 1 (H1), Bolling-Allerod (B/A) and YD events. At about 9.4 kyr B.P., a sudden change in the relative abundance of shallow to deep planktonic species probably indicates a sudden strengthening of the Kuroshio Current in the Okinawa Trough, which was synchronous with a rapid sea-level rise at 9.5-9.2 kyr B.P. in the ECS, Yellow Sea (YS) and South China Sea (SCS). The abundance of planktonic foraminiferal species, together with Mg/Ca based SST, exhibits millennial-scale oscillations during the Holocene, with 7 cold events (at about 1.7, 2.3-4.6, 6.2, 7.3, 8.2, 9.6, 10.6 cal. kyr BP) superimposed on a Holocene warming trend. This Holocene trend, together with centennial-scale SST variations superimposed on the last deglacial trend, suggests that both high and low latitude influences affected the climatology of the Okinawa Trough. (c) 2006 Elsevier B.V. All rights reserved.

海气热通量与东亚夏季风的关系

本文采用基于风切变的季风指数确定了多年季风爆发的时间；使用实测资料计算分析了2008年南海季风爆发前后海气通量的特征；基于COARE3.0算法，用NCEP2中海气要素再分析资料计算了海气热通量场并与NCEP2中原始热通量场进行了比较；利用EOF方法得到季风爆发早晚年份海气热通量场的时空特征；利用SVD方法分析了热通量场及海温场与季风的关系，初步探讨了海气热通量的变化影响季风爆发的过程和机理。结果表明： 1、2008年南海夏季风爆发期间热带气旋对海气要素的影响较大。动量交换系数与热量交换系数是风速的函数，曲线在风速为4m/s时有一个转折的过程。 2、海温的变化超前于季风爆发时间和强度的变化；热通量的变化超前于海温的变化。热通量通过海温这一中间过程对季风产生作用。 3、季风爆发时间和强度的变化受前期2至3个月时黑潮区域热通量变化的影响。此海域的热通量较大的时候，其后的季风爆发偏早、偏强；反之，季风爆发偏晚、偏弱。

大气季节内振荡对东亚夏季风活动的影响研究

利用ERA40逐日再分析资料、NCEP/NCAR2逐日再分析资料、中国740个测站日降水资料、上海台风研究所提供的西太平洋热带气旋资料、Kaplan等重建的月平均SSTA资料、NOAA逐日长波辐射（OLR）等资料，应用离散功率谱分析、带通滤波、EOF分析等统计方法，研究了东亚夏季风(EASM）的移动特征、东亚地区季节内振荡(ISO)的基本特征、季节内振荡对东亚夏季风活动的影响、季节内振荡对东亚夏季风异常活动的影响机理。主要结论如下： （1）综合动力和热力因素定义了可动态描述东亚夏季风移动和强度的指数，并利用该指数研究了东亚夏季风的爆发和移动的季节内变化及其年际和年代际变化特征。研究发现，气候平均东亚夏季风前沿分别在28候、33候、36候、38候、40候、44候出现了明显的跳跃。东亚夏季风活动具有显著的年际变率，主要由于季风前沿在某些区域异常停滞和突然跨越北跳或南撤引起，造成中国东部旱涝灾害频繁发生。东亚夏季风的活动具有明显的年代际变化，在1965年、1980年、1994年发生了突变，造成中国东部降水由“南旱北涝”向“南涝北旱”的转变。 （2）东亚季风区季节内变化具有10~25d和30~60d两个波段的季节内振荡周期，以30-60d为主。存在三个主要低频模态，第一模态主要表征了EASM在长江中下游和华北地区活动期间的低频形势；第二模态印度洋-菲律宾由低频气旋式环流控制，主要表现了ISO在EASM爆发期间的低频形势；第三模态主要出现在EASM在华南和淮河活动期间的低频形势。第一模态和第三模态是代表东亚夏季风活动异常的主要低频形势。 （3）热带和副热带地区ISO总是沿垂直切变风的垂直方向传播。因此，在南海-菲律宾东北风垂直切变和副热带西太平洋北风垂直切变下，大气热源激发菲律宾附近交替出现的低频气旋和低频反气旋不断向西北传播，副热带西太平洋ISO以向西传播为主。中高纬度地区，乌拉尔山附近ISO以向东、向南移动或局地振荡为主；北太平洋中部ISO在某些情况下向南、向西传播。 （4）季风爆发期，伴随着热带东印度洋到菲律宾一系列低频气旋和低频反气旋， 冷空气向南输送，10~25天和30~60天季节内振荡低频气旋同时传入南海加快了南海夏季风的爆发。在气候态下，ISO活动表现的欧亚- 太平洋（EAP）以及太平洋-北美（PNA）低频波列分布特征(本文提出的EAP和PNA低频波列与传统意义上的二维定点相关得到的波列不同)。这种低频分布形式使得欧亚和太平洋中高纬度的槽、脊及太平洋副热带高压稳定、加强，东亚地区的低频波列则成为热带和中高纬度ISO相互作用影响东亚夏季风活动的纽带。不同的阶段表现不同的低频模态，30~60d低频模态的转变加快了EASM推进过程中跳跃性；30-60d低频模态的维持使得EASM前沿相对停滞。 （5）30-60d滤波场，菲律宾海域交替出现的低频气旋和低频反气旋不断向西北传播到南海-西太平洋一带。当南海-西太平洋地区低频气旋活跃时，季风槽加强、东伸，季风槽内热带气旋（TC）频数增加；当南海-西太平洋低频反气旋活跃时，季风槽减弱、西退，TC处于间歇期，生成位置不集中。 （6）在El Nino态下，大气季节内振荡偏弱，北传特征不明显，但ISO由中高纬度北太平洋中部向南和副热带西太平洋向西的传播特征显著，东亚地区ISO活动以第三模态为主，EASM集中停滞在华南和淮河流域，常伴随着持续性区域暴雨的出现，易造成华南和江淮流域洪涝灾害，长江和华北持续干旱。在La Nina态下，大气季节内振荡活跃，且具有明显的向北传播特征，PNA低频波列显著，东亚地区ISO活动以第一模态单峰为主；EASM主要停滞在长江中下游和华北地区，这些地区出现异常持续强降水，华南和淮河流域多干旱；在El Nino态向La Nina态转换期，ISO活动以第一模态双峰为主，长江中下游常常出现二度梅。

泥河湾盆地大长梁剖面岩石磁学和环境磁学研究

The fluvio-lacustrine sequence in the Nihewan Basin is an important archive of late Pliocene-Pleistocene climate and environment changes in temperate northern China, which provides excellent sources of early human settlements in high latitude East Asia. The recent years have witnessed a considerable progress in the paleomagnetic dating of its stratigraphy, which has notably increased our understanding of a series of important issues such as the early human occupation in the Old World, the infilling history of the Nihewan Basin, and the chronological sequence of the Nihewan faunas. Up to now, the long-term paleoenvironmental changes directly retrieved from this basin, which might influence the evolution and expansion of early humans in the Nihewan Basin, are still poorly constrained, although several paleoclimatic records have been retrieved from this area. In this study, a combined mineral-magnetic and geochemical investigation was carried out on the fluvio-lacustrine sequence from the Dachangliang section at the eastern margin of the basin in order to reveal its rock magnetic and environmental magnetic characteristics and its implications for early human evolution in East Asia. The major findings and conclusions are listed as the following: First, there is an increased cooling coupled with an intensified aridification recorded in the fluvio-lacustrine sequence of the Dachangliang section. The cooling is related to an up-section decrease in propensity to chemical weathering as inferred from an increase in low-field susceptibility after cycling to 700 °C. Close to 700 °C, reacting chlorite is providing the iron source for newly formed very fine-grained ferrimagnetic minerals which enhances the susceptibility signal. The reactivity of chlorite after annealing at temperatures above 600 °C is documented with X-ray diffraction. Second, degrees of chemical weathering in the Nihewan Basin are further estimated by clay mineralogy (i.e. chlorite and illite contents and chlorite/illite ratio) and a series of major element proxies (i.e. Na2O/Al2O3 versus K2O/Al2O3 diagram, Al2O3-(CaO + Na2O)-K2O ternary diagram (A-CN-K), chemical index of alteration (CIA), (CaO + Na2O + MgO)/TiO2, (CaO + Na2O + MgO + K2O)/(TiO2 + Al2O3), CaO/Al2O3 and CaO/TiO2). The up-section decrease in propensity to chemical weathering suggested by the aforementioned rock mangetic measurement is further confirmed by these geochemical analyses. Combining the chemical weathering records from the Nihewan Basin, Chinese Loess Plateau, South China Sea and eastern China, we find that the consecutive decreasing trend in chemical weathering intensity during the late Cenozoic is ubiquitous across China. This pattern may result from a long-term decreasing East Asian summer monsoon and increasing East Asian winter monsoon, and thus a consecutive increasing of aridification and cooling in Asia during the Quaternary. Furthermore, the chemical weathering intensity increased from South China to North China during the Quaternary, in line with the decreasing East Asian summer monsoon and increasing East Asian winter monsoon and thus the gradually intensified aridification and cooling from South China to North China. Third, a combined mineral-magnetic and geochemical investigation provides evidences that the large-amplitude alterations of concentration of magnetic minerals mainly result from preservation/dissolution cycles of detrital magnetic minerals in alternately oxic and anoxic depositional environments. The preservation/dissolution model implies that the high-magnetic and low-magnetic cycles of this sedimentary sequence represent glacial and interglacial climate cycles, respectively. This contribute significnatly to our understanding of the link between climate and magnetic properties. Finally, the paleoclimatic implications of these rock magnetic and geochemical characteristics significantly increase our understanding of the general setting of early humans in high northern latitude in East Asia. We propose that the cold and dry climate may have contributed significantly to the expansion and adaptation of early humans, rather than bringing hardship, as is often thought. The relationship between magnetic properties and climate possibly provides valuable information on the climatic context of the Paleolithic sites in the basin, especially whether the occupation occurred during an interglacial or glacial period.

晚中新世以来中国北方风成沉积的磁性地层学和沉积学研究

The past two decades have witnessed an unprecedented growth of interest in the palaeoenvironmental significance of the Pleistocene loess deposits in northern China. However, it is only several years ago that the Tertiary red clay sequence underlying Pleistocene loess attracted much attention. One of the major advances in recent studies of eolian deposits on the Loess Plateau is the verification of the eolian origin for the Tertiary red clay sediments. The evidence of the eolian origin for the red clay is mainly from geochemical and sedimentological studies. However, sedimentological studies of the red clay deposits are still few compared with those of the overlying loess sediments. To date, the red clay sections located near Xifeng, Baoji, Lantian, Jiaxian, and Lingtai have been studied, with an emphasis on magnetostratigraphy. These sections have a basal age ranging from ～4.3 Ma to ～7.0 Ma. The thickness of the sections varies significantly, depending perhaps on the development of local geomorphological conditions and the drainage system. Although the stratigraphy of the red clay sections has been recorded in some detail, correlation of the red clay sequences has not yet been undertaken. Geological records (Sun J. et al., 1998) have shown that during glacial periods of the Quaternary the deserts in northem China were greatly expanded compared with modern desert distribution. During interglacial periods, desert areas contracted and retreated mostly to northwestern China because of the increase in inland penetration of monsoonal precipitation. According to pedogenic characteristics of the red clay deposits, the climatic conditions of the Loess Plateau is warmer and wetter generally in the Neogene than in the late Pleistocene. Panicle analyses show that grain size distribution of the red clay sequence is similar to that of the paleosols in the Pleistocene loess record, thus implying a relatively remote provenance of the red clay materials. However, the quantitative or semiquantitative estimates of the distance from the source region to the Loess Plateau during the red clay development remains to be investigated. In this study, magnetostratigraphic and sedimentological studies are conducted at two thick red clay sequences-Jingchuan and Lingtai section. The objectives of these studies are focused on further sedimentological evidence for the eolian origin of the red clay, correlation of red clay sequences, provenance of the red clay, and the palaeoclimate reconstruction in the Neogene. Paleomagnetic studies show that the Jingchuan red clay has a basal age of 8.0 Ma, which is 1 million years older than the previously studied Lingtai section. The Lingtai red clay sequence was divided into five units on the basis of pedogenica characteristics (Ding et al., 1999a). The Jingchuan red clay sequence, however, can be lithologically divided into six units according to field observations. The upper five units of the Jingchuan red clay can generally correlate well with the five units of the Lingtai red clay. Comparison of magnetic susceptibility and color reflectance records of four red clay sections suggests that the Lingtai red clay sequence can be the type-section of the Neogene red clay deposits in northern China. Pleistocene loess and modem dust deposits have a unimodal grain-size distribution. The red clay sediments at Jingchuan and Lingtai also have a unimodal grain-size distribution especially similar to the paleosols in the Pleistocene loess record. Sedimentological studies of a north-south transect of loess deposits above S2 on the Loess Plateau show that loess deposits had distinct temporal and spatial sedimentary differentiation. The characteristics of such sedimentary differentiation can be well presented in a triangular diagram of normalized median grain size, normalized skewness, and normalized kurtosis. The triangular diagrams of the red clay-loess sequence at Lingtai and Jingchuan indicate that loess-paleosol-red clay may be transported and sorted by the same agent wind, thus extending the eolian record in the Loess Plateau from 2.6 Ma back to about 8.0 Ma. It has been recognized that during the last glacial maximum (LGM) the deserts in northern China had a distribution similar to the present, whereas during the Holocene Optimum the deserts retreated to the area west of the Helan Mountains. Advance-retreat cycles of the deserts will lead to changes in the distance of the Loess Plateau to the dust source regions, thereby controlling changes in grain size of the loess deposited in a specific site. To observe spatial changes in sedimentological characteristics of loess during the last glacial-interglacial cycle, the texture of loess was measured along the north-south transect of the Loess Plateau. Since the southern margin of the Mu Us desert during the LGM is already known, several models of grain size parameters versus the minimum distance from the source region to depositional areas were developed. According to these semiquantitative models, the minimum distance from the source region to Lingtai and Jingchuan areas is about 600 km during the Neogene. Therefore the estimated provenance of the Tertiary red clay deposits is the areas now occupied by the Badain Jaran desert and arid regions west of it. The ratio of the free iron to total iron concentration attests to being a good proxy indicator for the summer monsoon evolution. The Lingtai Fe_20_3 ratio record shows high values over three time intervals: 4.8-4.1 Ma, 3.4-2.6 Ma, and during the interglacial periods of the past 0.5 Ma. The increase in summer monsoon intensity over the three intervals also coincides with the well-developed soil characteristics. It is therefore concluded that the East-Asia summer monsoon has experienced a non-linear evolution since the late Miocene. In general, the East Asia summer monsoon was stronger in Neogene than in Quaternary and the strongest East Asia summer monsoon may occur between 4.1 and 4.8 Ma. The relatively small ice volume and high global temperature may be responsible for the strong summer monsoon during the early Pliocene.