基于查尔酮合酶基因探讨鲜卑花的种群动态历史与遗传分化

以高山灌木鲜卑花为研究材料,收集其在中国全部分布区域内的13个居群共139个个体,以查尔酮合酶基因(CHS)的内含子区域为分子标记,探讨鲜卑花的种群动态历史、遗传分化的时间与成因。在鲜卑花中CHS共鉴定了29种单倍型,单倍型多样性和核苷酸多样性分别为0.9248和0.007 545,遗传变异大;贝叶斯分析说明鲜卑花种内遗传分化的时间始于4.37 Ma左右。中性检验与歧点分布分析一致表明鲜卑花在近期经历了明显的居群扩张,估算的扩张时间在55.8 ka左右。研究结果表明鲜卑花在末次冰期间冰阶时期从冰期避难所向外经历了明显的居群扩张;而青藏高原的整体隆升导致的环境剧变,加剧了鲜卑花居群间的遗传分化。     

基于GIS的青藏高原地区四种高山植物的空间遗传格局

青藏高原地区景观特征影响着高山植物的现代遗传格局。基于叶绿体DNA(cpDNA)变异数据,运用GIS空间插值方法和Monmonier算法,分析了青藏高原地区4种高山植物长花马先蒿(Pedicularis longiflora)、西川红景天(Rhodiola alsia)、窄叶鲜卑花(Sibiraea angustata)和西藏沙棘(Hippophae tibetana)的遗传多样性和遗传分化景观格局。结果表明:在4种高山植物的遗传景观格局中,高值区域主要位于东喜马拉雅-横断山脉地区,每种植物的地理隔离也位于这个地区;Partial Mantel test检测表明,地理隔离均显著影响4种植物种群的基因交流,验证了长期地理隔离造成的种群分化是产生该地区遗传格局的主要原因。     

青藏高原东部窄叶鲜卑花碳、氮、磷化学计量特征

为了探究青藏高原东部窄叶鲜卑花(Sibiraea angustata)灌木不同器官碳(C)、氮(N)、磷(P)含量的分配格局及其生态化学计量特征,该文采用分层随机抽样方法布设样地,选择16个窄叶鲜卑花灌丛样地,分别采集窄叶鲜卑花灌木根、茎、叶、当年枝和果等植物器官样品,并分析样品C、N、P含量及其计量比。结果表明:C、N、P在不同器官中的含量分别表现为茎当年枝果根叶,叶果当年枝茎根,果叶当年枝根茎。窄叶鲜卑花各器官中C含量相对稳定,N、P含量变异系数较大,在根部的变异系数最大。在不同器官中N:P的范围为7.12–12.41,其值变化不大,N:P变异系数的最小值在当年枝中,说明N:P在当年枝中的内稳性较高。在该灌木植物体中C与N之间、C与P之间呈极显著的负相关关系,C对N、P具有稀释作用;N与P呈极显著正相关关系,N与P间具有较好的耦合协同性。分析发现:窄叶鲜卑花不同器官C、N、P化学计量特征在一定程度上符合内稳态理论和生长速率理论,其元素分配与器官所执行的功能密切相关;同时指出在物种水平上应当谨慎使用生态化学计量比来判断养分的限制情况。     

分子标记技术及其在植物遗传育种中的应用

本对遗传标记技术的发展历程作了简要的回顾。概述了目前常用的RFLP和RAPD等分子标记技术的基本原理和特点,及其在构建分子遗传图谱、品种间遗传关系分析、进行基因定位和测定遗传距离等遗传育种中的应用。     

早期鲜卑人和动物骨骼的稳定同位素分析

本文对呼伦贝尔地区扎赉诺尔、团结和东乌珠尔早期鲜卑墓地出土的人和动物骨骼进行了稳定同位素分析,以期揭示早期鲜卑的食物结构和生计方式。C、N稳定同位素分析结果表明,早期鲜卑人的食物来源兼具C_3类和C_4类,其中C_4类食物很可能来自其从事的少量粟作农业。人具有较高的δ~(15)N值,且与动物的δ~(15)N值差异较大,表明人的营养级较高,肉食资源在食物结构中占据较大比重,这可能来自于早期鲜卑人所从事的游牧及狩猎经济的贡献。C、N、S稳定同位素分析结果表明,动物和人的食物来源来自于当地的陆生系统,而个体马(DW M3(1))具有较高的δ~(13)C和δ~(15)N值以及明显不同于其他样品的异常高的δ~(34)S值,说明此个体可能属于来自于其他地质环境的"外来者"。     

农业区游牧民族饮食文化的滞后性——基于大同东信广场北魏墓群人骨的稳定同位素研究

不同地域的人群具有不同的饮食传统和饮食文化。然而,当人们持续不断的直接或间接接触时,一方或双方原有的饮食文化将会产生变化,如拓跋鲜卑的饮食文化就经历了从游牧向农业的转变。本文对山西大同东信广场北魏墓群26例人骨进行了C、N稳定同位素分析,结果 (δ~(13)C值为-11.5±2.7‰,n=26;δ~(15)N值为9.8±1.2‰,n=26)显示,先民的食物类型差异较大,并包含大量的肉食资源。研究表明,以C_3类食物为主的先民主要放牧或狩猎,以C_4类食物为主的先民主要以种植粟、黍等C_4型农作物喂养家畜。大同东信广场北魏墓群人群中两种不同饮食传统的存在,显示游牧民族新的饮食习惯(以粟作农业产品为食)的形成滞后性于北魏政权的建立,这可能与气候变冷及他们的排斥有关。     

脉孢霉两对基因顺序四分子分析

真菌和单细胞藻类四分子分析能够利用单次减数分裂的4个产物进行独特的遗传分析, 是帮助人们直观地理解遗传机制的重要手段, 已被用于高等生物遗传作图。文章运用孟德尔遗传规律、遗传重组机理与遗传作图原理, 分析了两对基因杂交的子囊、子囊孢子类型间关系; 推导出了两对基因顺序四分子分析的完整步骤。     

贵州地方水稻种质资源籼-粳遗传分化的InDel分子标记研究

本研究利用36对InDel分子标记引物对贵州地方水稻种质的籼-粳遗传分化和亲缘关系进行分析,结果表明,82份贵州地方栽培稻中49份为粳稻,33份为籼稻,贵州地方栽培稻“禾”品种主要属于粳稻,而“谷”品种主要为籼稻。基于Nei氏遗传距离的亲缘关系分析表明在粳稻群体和籼稻群体中均存在与野生稻亲缘关系近的品种,其中的粳稻品种与野生稻的遗传关系比之籼稻品种近。而基于MCMC算法的遗传结构分析揭示了贵州地方籼稻品种中存在较为复杂的遗传结构。分子变异分析显示,粳稻和籼稻品种的遗传变异主要来自亚种内,遗传多样性分析表明其亚种内籼稻品种的遗传多样性略高于粳稻品种。研究结果揭示了贵州省黔东南地区栽培稻种质资源的籼-粳分化程度、遗传关系及其遗传多样性。     

中国西南地区3个隔离人群遗传亚结构分析

中国西南地区分布着众多少数民族,同时也包含许多地理和遗传隔离的人群,然而这些族群的遗传结构,特别是父系遗传结构缺乏深度解析。本研究采用Y染色体捕获及Illumina测序技术,对西南地区3个隔离人群男性无关个体样本,包括四川平武县的白马人、石棉县的木雅人及云南景洪市空格人,通过定点复合扩增检测,直接计数法计算相关单倍群频率,应用Past3.0软件进行PCA (principle component analysis, PCA)主成分分析并绘制群体聚类树,研究了3个族群的父系遗传结构,并探讨其遗传亚结构关系。本研究共观察到云南空格人三种Y染色体单倍群、四川白马人四种Y染色体单倍群以及木雅人五种Y染色体单倍群。结果表明,空格人与佤族的父系遗传关系最近;而白马人和木雅人主要集中在D单倍群及其下游,研究提示着白马人和四川羌族的父系遗传关系最近;木雅人与昌都地区藏族和林芝地区藏族父系遗传关系最近。本文对不同族群遗传结构的分析,丰富了我国隔离人群遗传关系的研究成果。     

窄叶鲜卑花(Sibiraea angustata)nrDNA ITS和cpDNA trnL-F序列分子进化特点的分析

应用PCR产物直接测序法分析了窄叶鲜卑花居群间nrDNA(核糖体DNA)ITS序列和cpDNA(叶绿体DNA)trnL-F的碱基差异,并与cpDNAtrnS-G序列和rpl20-rps12序列进行比较,从而初步研究两套植物基因组的变异速率。采用改良的CTAB法从硅胶干燥的窄叶鲜卑花叶片中提取总DNA,并对nrDNA ITS和cpDNAtrnL-F区域进行扩增、纯化、测序。nrDNA ITS序列共有601 bp,有变异位点3处,变异位点百分率为0.05%,(G+C)含量为41.4%。cpDNAtrnL-F序列共有927 bp,有变异位点1处,变异位点百分率0.01%,(G+C)含量为32.6%,两种序列的核苷酸多样性非常低。比较发现,窄叶鲜卑花nrDNA ITS区域较cpDNAtrnS-G序列和rpl20-rps12序列保守,变异速率较慢,比cpDNAtrnL-F序列变异速率稍快。通过对ITS序列单倍型(haplotype)进行分析发现,窄叶鲜卑花现有分布范围经历了居群近期范围扩张,与叶绿体基因组(trnS-G和rpl20-rps12序列)得出的结论一致。因此,窄叶鲜卑花nrDNA ITS序列适合该种的谱系地理学研究。     

Genetic analyses of Xianbei populations about 1,500–1,800 years old

To understand the profile of genetic structure of Xianbei and trace its impacts on the formation and development of the minorities from northern China, we analyzed the sequences of the hypervariable segment I (HVS-I, 16.035–16.398) in mtDNA control region of 17 Tuoba Xianbei remains from Shangdu Dongdajing cemetery (Inner Mongolia). Its haplotype diversity and nucleotide diversity were 0.971 ± 0.032 and 0.0184 ± 0.010, respectively, and the haplogroup status presented 29.5% C, 23.5% D4, 17.6% D5, 17.6%A, 5.9% B and 5.9% G. When the data from Qilang Mountain Tuoba remains and other relevant populations were considered, we found that Dongdajing Tuoba Xianbei presented the closest genetic affinity to Qilang Mountain Tuoba Xianbei. Tuoba Xianbei and Murong Xianbei showed a significant differentiation in the maternal lineages. Tuoba Xianbei may contribute to the gene pool of some northern minorities, and it may mix with Xiongnu in northern China.     

Genetic analysis on Tuoba Xianbei remains excavated from Qilang Mountain Cemetery in Qahar Right Wing Middle Banner of Inner Mongolia

Sixteen sequences of the hypervariable segment I (HVS-I, 16039-16398) in mtDNA control region from ancient Tuoba Xianbei remains excavated from Qilang Mountain Cemetery were analyzed. In which, 13 haplotypes were found by 25 polymorphic sites. The haplotype diversity and nucleotide diversity were 0.98 and 0.0189, respectively, and the mean of nucleotide number differences was 6.25. Haplogroup analysis indicates these remains mainly belong to haplogroup C (31.25%) and D (43.75%). According to the published data were considered, we can suggest that the Tuoba Xianbei presented a close genetic affinity to Oroqen, Outer Mongolian and Ewenki populations, especially Oroqen.     

Molecular genetic analysis of remains from Lamadong cemetery, Liaoning, China

The Xianbei existed as a remarkable nomadic tribe in northeastern China for three dynasties: the Han, Jin, and Northern-Southern dynasties (206 BC to 581 AD) in Chinese history. A very important subtribe of the Xianbei is the Murong Xianbei. To investigate the genetic structure of the Murong Xianbei population and to address its genetic relationships with other nomadic tribes at a molecular level, we analyzed the control region sequences and coding-region single nucleotide polymorphism markers of mtDNA from the remains of the Lamadong cemetery of the Three-Yan Culture of the Murong Xianbei population, which is dated to 1,600-1,700 years ago. By combining polymorphisms of the control region with those from the code region, we assigned 17 individuals to haplogroups B, C, D, F, G2a, Z, M, and J1b1. The frequencies of these haplogroups were compared with those of Asian populations and a multidimensional scaling graph was constructed to investigate relationships with other Asian populations. The results indicate that the genetic structure of the Lamadong population is very intricate; it has haplogroups prevalent in both the Eastern Asian and the Siberian populations, showing more affinity with the Eastern Asian populations. The present study also shows that the ancient nomadic tribes of Huns, Tuoba Xianbei, and Murong Xianbei have different maternal genetic structures and that there could have been some genetic exchange among them.     

A western Eurasian male is found in 2000‐year‐old elite Xiongnu cemetery in Northeast Mongolia

We analyzed mitochondrial DNA (mtDNA), Y‐chromosome single nucleotide polymorphisms (Y‐SNP), and autosomal short tandem repeats (STR) of three skeletons found in a 2,000‐year‐old Xiongnu elite cemetery in Duurlig Nars of Northeast Mongolia. This study is one of the first reports of the detailed genetic analysis of ancient human remains using the three types of genetic markers. The DNA analyses revealed that one subject was an ancient male skeleton with maternal U2e1 and paternal R1a1 haplogroups. This is the first genetic evidence that a male of distinctive Indo‐European lineages (R1a1) was present in the Xiongnu of Mongolia. This might indicate an Indo‐European migration into Northeast Asia 2,000 years ago. Other specimens are a female with mtDNA haplogroup D4 and a male with Y‐SNP haplogroup C3 and mtDNA haplogroup D4. Those haplogroups are common in Northeast Asia. There was no close kinship among them. The genetic evidence of U2e1 and R1a1 may help to clarify the migration patterns of Indo‐Europeans and ancient East‐West contacts of the Xiongnu Empire. Artifacts in the tombs suggested that the Xiongnu had a system of the social stratification. The West Eurasian male might show the racial tolerance of the Xiongnu Empire and some insight into the Xiongnu society. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.     

Population origins in Mongolia: genetic structure analysis of ancient and modern DNA

In the present study, nuclear (autosomal and Y-chromosome short tandem repeats) and mitochondrial (hypervariable region I) ancient DNA data previously obtained from a 2,300-year-old Xiongnu population of the Egyin Gol Valley (south of Lake Baikal in northern Mongolia) (Keyser-Tracqui et al. 2003 Am. J. Hum. Genet. 73:247-260) were compared with data from two contemporary Mongolian populations: one from the same location (Egyin Gol Valley plus a perimeter of less than 100 km around the valley), and one from the whole of Mongolia. The principal objective of this comparative analysis was to assess the likelihood that genetic continuity exists between ancient and present-day Mongolian populations. Since the ancient Xiongnu sample might have been composed of some of the ancestors of the present-day Yakuts, data from a present-day Yakut population, as well as published data from Turkish populations, were also included in the comparative analysis. The main result of our study was the genetic similarity observed among Mongolian samples from different periods and geographic areas. This result supports the hypothesis that the succession over time of different Turkic and Mongolian tribes in the current territory of Mongolia resulted in cultural rather than genetic exchanges. Furthermore, it appears that the Yakuts probably did not find their origin among the Xiongnu tribes, as we previously hypothesized.     

Nuclear and mitochondrial DNA analysis of a 2,000-year-old necropolis in the Egyin Gol Valley of Mongolia

DNA was extracted from the skeletal remains of 62 specimens excavated from the Egyin Gol necropolis, in northern Mongolia. This burial site is linked to the Xiongnu period and was used from the 3rd century b.c. to the 2nd century a.d. Three types of genetic markers were used to determine the genetic relationships between individuals buried in the Egyin Gol necropolis. Results from analyses of autosomal and Y chromosome short tandem repeats, as well as mitochondrial DNA, showed close relationships between several specimens and provided additional background information on the social organization within the necropolis as well as the funeral practices of the Xiongnu people. To the best of our knowledge, this is the first study using biparental, paternal, and maternal genetic systems to reconstruct partial genealogies in a protohistoric necropolis.     

Reanalysis of Eurasian population history: ancient DNA evidence of population affinities

Mitochondrial hypervariable region I genetic data from ancient populations at two sites in Asia-Linzi in Shandong (northern China) and Egyin Gol in Mongolia-were reanalyzed to detect population affinities. Data from 51 modern populations were used to generate distance measures (Fst's) to the two ancient populations. The tests first analyzed relationships at the regional level and then compiled the top regional matches for an overall comparison to the two probe populations. The reanalysis showed that the Egyin Gol and Linzi populations have clear distinctions in genetic affinity. The Egyin Gol population as a whole appears to bear close affinities with modern populations of northern East Asia. The Linzi population seems to have some genetic affinities with the West, as suggested by the original analysis, although the original attribution of "European-like" seems to be misleading. We suggest that the Linzi individuals are potentially related to early Iranians, who are thought to have been widespread in parts of Central Eurasia and the steppe regions in the first millennium B.C., although some significant admixture between a number of populations of varying origin cannot be ruled out. We also examine the effect of sequence length on this type of genetic data analysis and discuss the results of previous studies on the Linzi sample.     

An extensive analysis of Y-chromosomal microsatellite haplotypes in globally dispersed human populations

The genetic variance at seven Y-chromosomal microsatellite loci (or short tandem repeats [STRs]) was studied among 986 male individuals from 20 globally dispersed human populations. A total of 598 different haplotypes were observed, of which 437 (73.1%) were each found in a single male only. Population-specific haplotype-diversity values were.86-.99. Analyses of haplotype diversity and population-specific haplotypes revealed marked population-structure differences between more-isolated indigenous populations (e.g., Central African Pygmies or Greenland Inuit) and more-admixed populations (e.g., Europeans or Surinamese). Furthermore, male individuals from isolated indigenous populations shared haplotypes mainly with male individuals from their own population. By analysis of molecular variance, we found that 76.8% of the total genetic variance present among these male individuals could be attributed to genetic differences between male individuals who were members of the same population. Haplotype sharing between populations, phi(ST) statistics, and phylogenetic analysis identified close genetic affinities among European populations and among New Guinean populations. Our data illustrate that Y-chromosomal STR haplotypes are an ideal tool for the study of the genetic affinities between groups of male subjects and for detection of population structure.     

Genetic polymorphisms of nine X-STR loci in four population groups from Inner Mongolia, China

Nine short tandem repeat （STR） markers on the X chromosome （DXS101, DXS6789, DXS6799, DXS6804, DXST132, DXST133, DXS7423, DXS8378, and HPRTB） were analyzed in four population groups （Mongol, Ewenki, Oroqen, and Daur） from Inner Mongolia, China, in order to learn about the genetic diversity, forensic suitability, and possible genetic affinities of the populations. Frequency estimates, Hardy-Weinberg equilibrium, and other parameters of forensic interest were computed. The results revealed that the nine markers have a moderate degree of variability in the population groups. Most heterozygosity values for the nine loci range from 0.480 to 0.891, and there are evident differences of genetic variability among the populations. A UPGMA tree constructed on the basis of the generated data shows very low genetic distance betweent Mongol and Han （Xi＇an） populations. Our results based on genetic distance analysis are consistent with the results of earlier studies based on linguistics and the immigration history and origin of these populations. The minisatellite loci on the X chromosome studied here are not only useful in showing significant genetic variation between the populations, but also are suitable for human identity testing among Inner Mongolian populations.