突尼斯非洲跳鼠(Jaculus jaculus)和埃及跳鼠(J.orientalis)群体的等位酶多态及遗传分化(英文)

运用16种酶蛋白编码的23个遗传座位对突尼斯非洲跳鼠(Jaculus jaculus)和埃及跳鼠(J. orientalis)自然群体的遗传变异和分化进行了电泳分析。结果表明,与其他啮齿动物等哺乳动物的相关数据比较,发现这两个种群体的遗传变异水平较低。非洲跳鼠群体的观测杂合度 (H_obs) 为0.08—0.19,多态座位百分比(P)为26.2%—45.2%,每个座位的平均等位基因数(A)为1.1—1.4;埃及跳鼠的H_obs为0.10—0.15,P为29.3%—44.1%,A为1.1—1.7。两个种群体各自的遗传分化程度较低(非洲跳鼠和埃及跳鼠的F_st分别为0.0017和0.0019)。而两个种群体间的F_st为0.607（P<0.05）,表明两个种之间高度的遗传分化。本研究支持这两个种分类地位的合法性,并强调了地理因素（环境类型和生物气候阶段）对两个种遗传结构的影响。     

中国沿海瘤背石磺不同地理群体遗传多样性的ISSR标记研究

研究以盐城(YC)、上海(SH)、温州(WZ)、厦门(XM)、深圳(SZ)、海南(HN)6个不同地理群体的瘤背石磺为试验材料,利用ISSR分子标记进行了遗传多样性研究。结果表明,6个地理群体的多态位点百分率在54.20%-70.99%之间,Nei’s基因多样性指数和Shannon’s信息指数分别在0.156 4-0.219 1和0.242 1-0.332 4之间。AMOVA分子变异分析表明,瘤背石磺47.25%的变异发生在群体间,52.75%的变异发生在群体内,居群内的遗传变异大于居群间的遗传变异。平均Fst值为0.4725,种间分化系数(Gst)为0.370 5,基因流(Nm)为0.849 7,表明6个地理群体间已经发生了较大程度的遗传分化,其中推断遗传漂变可能是影响群体分化的主要因素之一。     

甘肃金鳟遗传资源评价及其与日本金鳟和道氏虹鳟遗传分化研究

为分析甘肃金鳟遗传资源状况, 研究利用18 个微卫星DNA 标记, 对甘肃金鳟、日本金鳟和道氏虹鳟3 群体各50 尾个体进行了遗传分析, 以评价甘肃金鳟遗传资源状况并研究其与日本金鳟和道氏虹鳟遗传分化情况。结果表明甘肃金鳟具有较丰富的遗传变异, 15 个微卫星DNA 座位共获得了51 个等位基因, 有效等位基因数(Ne)为1.13, 多态信息含量(PIC)为0.440, 平均观察杂合度(Ho)和期望杂合度(He)分别为0.430 和0.498。在Hardy-Weinberg 平衡条件下, 进行了P 检验, 发现3 个群体均有位点发生了显著偏离; 对3 个群体进行了Fst 值计算, 表明群体间存在着一定程度的遗传分化, 但遗传变异绝大部分存在于品种内。综合分析,认为甘肃金鳟遗传性状基本稳定, 遗传变异度较高, 遗传多样性相对丰富, 具有较大的遗传潜力, 与道氏虹鳟和日本金鳟群体间分化明显, 人工选育对群体的遗传变异产生了一定的影响。研究结果对甘肃金鳟的保种、选育及其合理的推广应用具有一定的指导作用。       

中国东部沿海水仙归化群体的遗传多样性

为揭示我国东部归化水仙(Narcissus tazetta var. chinensis)的群体遗传多样性,利用2个叶绿体基因mat K和trn H-psb A片段对采自沪、浙、闽的5个代表群体的49株水仙进行了评估。结果表明,双基因联合序列的总长为1443bp,共定义6个单倍型,各归化群体的遗传多样性水平为DLSYPTDNJD=ZZCMD。AMOVA分析表明,群体内变异为遗传变异的主要来源(91.98%),群体间的遗传分化较低(Fst=0.080 22)。群体物种水平上的谱系结构不显著(Nst=0.020Gst=0.031;P0.05)。Mantel检验表明水仙群体间的遗传距离与地理距离呈显著的线性相关(r=0.929,P=0.02 0.05)。中性检验和错配分布分析结果均暗示水仙群体背离了快速扩张模型的假设。单倍型分布的中介网络图结合系统发育NJ树均将所有群体划分为2大分支。因此,我国东部沿海水仙归化群体整体遗传多样性水平较低,各群体间遗传分化较弱,遗传变异主要来自群体内,物种近期未经历扩张事件,可能是基因流受海岛隔离、自身生物学特征、生境异质性与及人为干扰的综合作用影响。     

新疆四种荒漠跳鼠肠道菌群多样性与功能的比较

肠道菌群是维持机体健康的重要组成部分,了解动物肠道菌群多样性有助于认识和理解动物的生态学适应。已有报道表明荒漠沙鼠肠道微生物有助于其对荒漠环境的适应,但对于广泛分布于荒漠环境的跳鼠的肠道微生物群落结构、多样性的研究尚不明确。本研究以栖息于新疆荒漠地区的跳鼠科(Dipodidae)为对象,采用16S rRNA高通量测序技术对荒漠跳鼠4个亚科的代表物种三趾跳鼠(Dipus sagitta)、五趾跳鼠(Orientallactage sibirica)、长耳跳鼠(Euchoreutes naso)和三趾心颅跳鼠(Salpingotus kozlovi)的肠道微生物进行分析。共获得1557065条有效序列,发现2708个ASV,归属于20个门、50个纲、71个目、142个科和336个属。Alpha多样性指数中,长耳跳鼠和三趾心颅跳鼠组的ACE指数和Chao1指数显著低于其他两组,而Shannon指数和Simpson指数在4组样品中无显著差异。主坐标分析(PCoA)结果表明,4种跳鼠的肠道菌群结构具有显著差异。LEfSe分析表明,4种跳鼠肠道菌群共有10个显著差异的细菌菌属,其中大部分归属拟杆菌...     

基于线粒体COI序列变异的高原鼢鼠种群遗传分化研究

基于线粒体COI基因序列对高原鼢鼠7个地理种群的遗传多样性、遗传分化和基因流进行分析,158条COI基因序列中发现了570个变异位点,界定了54个COI单倍型。总体单倍型多样性指数Hd为0.911,种群单倍型多样性在0.278—0.964之间,高原鼢鼠的种群遗传多样性较高。群体总的遗传分化系数Fst为0.611,群体间的基因流Nm在-0.020—3.700之间,部分地理种群之间的遗传分化程度高,基因流弱。AMOVA分子变异分析显示,高原鼢鼠的遗传变异主要来自种群之间(77.56%),种群内部的遗传变异较低(22.44%)。中性检验(P0.01)与错配分析显示高原鼢鼠种群经历了群体扩张事件。IBD未检测到地理距离与种群间遗传距离的显著性相关关系(R2=0.124,P=0.118)。综合分析认为,高原鼢鼠不同地理种群间遗传分化的原因除地理隔离外,还与迁移扩散方式、进化过程和其他环境因素有关。     

阿拉善荒漠区两种优势跳鼠种间营养生态位

营养生态位作为生态位理论的重要维度之一，不仅能够表现出物种的营养需求特征，而且可以反映物种在生态系统中的营养层级、功能地位以及物种间的营养关系。动物不同组织中的碳、氮稳定同位素比值可反映某一物种在不同时间段的食性信息，因而对探讨物种间摄食、栖息地资源利用和营养生态位的变化具有重要指示作用。以2017年在阿拉善荒漠实验区采用铗日法所捕获的三趾跳鼠（Dipus sagitta）和五趾跳鼠（Allactaga sibirica）为研究对象，测定其脱脂毛发与骨骼组织的δ¹³C和δ¹⁵N比值，分析探讨2种小型啮齿动物的营养级与营养生态位变化以及摄食策略与资源分配机制。结果表明：无论从长期时间尺度（一生）还是短期时间尺度（季节）分析，结果都一致表现出三趾跳鼠与五趾跳鼠种间营养生态位重叠面积（OA）值为0‰²，种间营养生态位发生分离；三趾跳鼠的营养级显著低于五趾跳鼠的营养级，但其营养生态位面积却大于五趾跳鼠；随着季节的变化，三趾跳鼠与五趾跳鼠的摄食范围和营养生态位面积均呈现出春季最大，夏季减小，秋季再增加的趋势。两种跳鼠的营养生态位变化与摄食策略符合生态位分化假说，二者通过种间营养生态位分化实现同域共存。     

东海海域口虾蛄种群遗传多样性

为准确掌握中国沿海口虾蛄(Oratosquilla oratoria)种群遗传结构、合理开发利用其资源,采用线粒体DNA(mt DNA)细胞色素氧化酶Ⅰ(COⅠ)序列分析方法检测东海海域(庙子湖岛、南韭山、大陈岛、南麂岛)口虾蛄种群遗传多样性,并与黄渤海群体和南海群体进行比较分析(基因序列来源于Gen Bank)。经PCR扩增与测序获得100条658 bp的东海海域口虾蛄COⅠ基因序列,基于这些序列分析得到的变异位点数、单倍型数、单倍型多样性指数与核苷酸多样性指数分别为60、60、0.963±0.011和0.005 94±0.000 44,分析认为东海海域口虾蛄具有较高的单倍型多样性和较高的核苷酸多样性。单倍型分子系统树、分子方差分析及两两群体间的遗传分化系数(Fst)分析结果表明,东海海域口虾蛄遗传变异主要来自于群体内(Fst=﹣0.007 78,P0.05),各地理群体间遗传分化不显著,Fst值范围为﹣0.016 53~﹣0.009 08(P0.05),它们可能进行了一定程度的基因交流;通过与黄渤海群体及南海群体基因序列比较分析,口虾蛄东海群体、黄渤海群体与南海群体遗传变异主要来自于群体间(Fst=0.849 71,P0.01),且单倍型分子系统树存在2个显著分化的单倍型类群。东海群体与黄渤海群体间存在显著的遗传分化(Fst=0.884 58,P0.01),而与南海群体间不存在显著的遗传分化(Fst=0.020 44,P0.05),这种遗传结构模式可能与历史上的气候变化及所处海域海洋环境条件相关。建议今后对中国沿海口虾蛄资源进行开发利用时,将黄渤海群体看作一个管理单元,东海群体与南海群体看作一个管理单元。     

记陕西蓝田晚中新世灞河组4种跳鼠(Dipodidae,Rodentia)化石

描述了陕西蓝田晚中新世早期灞河组的4属4种跳鼠:蓝田原跳鼠(新种)(Protalacta- ga lantianensis sp.nov.)、副跳鼠(未定种)(Paralactaga sp.)、原始三趾心颅跳鼠(新种)(Sal- pingotus primitivus sp.nov.)和小五趾心颅跳鼠(新种)(Cardiocranius pusillus sp.nov.)。蓝田原跳鼠兼有原跳鼠和副跳鼠的特征,可能是原跳鼠向副跳鼠进化过程中产生的一种过渡类型。副跳鼠和原始三趾心颅跳鼠及小五趾心颅跳鼠分别代表了副跳鼠属在中国的最早记录和心颅跳鼠亚科(Cardiocraniinae)在地史上的首次出现。4种跳鼠指示了蓝田地区当时的自然环境可能比现代更加干旱。     

内蒙古阿左旗乌兰塔塔尔地区中渐新世的林跳鼠科化石

本文记述的乌兰塔塔尔地区林跳鼠科化石计有中亚副蹶鼠(Parasminthus asiae-entralis)、党河副蹶鼠(P. tangingoli)、小副蹶鼠(P. parvulus)、邱氏戈壁蹶鼠(Gobiosminthus qiui gen. et sp. nov.)、?戈壁蹶鼠未定种(Gobiosminthus sp.)和童氏沙漠蹶鼠(Shamosminthus tongi gen. et sp. nov.)3属6种.对副蹶鼠属各种的种内变异和种间差异、我国早第三纪林跳鼠类的系统关系以及早期林跳鼠与仓鼠间的一些形态差别做了概要的阐述和讨论.     

Karyotypic variation in two species of jerboas Jaculus jaculus and Jaculus orientalis (Rodentia, Dipodidae) from Tunisia

The karyotypes of the lesser Egyptian jerboa Jaculus jaculus and the greater Egyptian jerboa Jaculus orientalis from Tunisia are described and compared with available data particularly from Egypt. The species examined have a similar karyotype consisting of 2n = 48 chromosomes and a fundamental number of autosomes (NFa) varying from 88 to 90 in J. jaculus and from 84 to 88 in J. orientalis. The X chromosome is submetacentric in both species, while the Y is submetacentric in J. orientalis and acrocentric in J. jaculus. Most of the autosomes are meta/submetacentric but the small pairs 22 - 23 in J. jaculus and 20-23 in J. orientalis are frequently acrocentric, yielding considerable differences in the NFa within and among species. Morphological variation in these small pairs of autosomes and/or in the Y chromosome in J. orientalis may distinguish populations of the two species from Egypt and Tunisia. The differences observed either between Egypt and Tunisia or between the Tunisian Jaculus species are probably associated with chromosomal rearrangements such as pericentric inversions or heterochromatin variation. They appear of lesser magnitude than other changes (especially molecular) that have occurred during the evolution of this genus.     

A comparative analysis of the rate of meiosis, chiasma frequency and terminalization in the Jerboas Allactaga and Jaculus (Rodentia: Dipodidae) in Egypt

The rate of seven meiotic stages (zygotene-pachytene, diplotene-diakinesis, metaphase I, anaphase I, metaphase II, anaphase II, and quartet) was studied in the jerboas Jaculus jaculus jaculus, Jaculus orientalis, and Allactaga tetradactyla, chiasma frequency and terminalization being examined only in J. jaculus and J. orientalis, and compared with the previous data concerning A. tetradactyla. Significant differences in the rate of meiosis, frequency of bivalent types, and frequency of interstitial and distal or terminal chiasmata per genome length were observed between A. tetradactyla and the two congeneric species J. jaculus and J. orientalis. Differences of these parameters among individuals within each species are also discussed in detail.     

Cryptic divergence and strong population structure in the colonial invertebrate Pycnoclavella communis (Ascidiacea) inferred from molecular data

We studied sequence variation in the mitochondrial gene cytochrome c oxidase subunit I (COI) for 135 individuals from eight Mediterranean populations of the colonial ascidian Pycnoclavella communis across most of its presently known range of distribution in the Mediterranean. Three haplotypes from Atlantic locations were also included in the study. Phylogenetic, phylogeographic and population genetic analyses were used to unravel the genetic variability within and between populations. The study revealed 32 haplotypes for COI, 29 of them grouped within two Mediterranean lineages of P. communis (mean nucleotide divergence between lineages was 8.55%). Phylogenetic and network analyses suggest the possible existence of cryptic species corresponding to these two lineages. Population genetic analyses were restricted to the five populations belonging to the main genetic lineage, and for these localities we compared the information gleaned from COI sequence data and from eight microsatellite loci. A high genetic divergence between populations was substantiated using both kinds of markers (COI, global Fst=0.343; microsatellite loci, global Fst=0.362). There were high numbers of private haplotypes (COI) and alleles (microsatellites) in the populations studied. Restricted gene flow and inbreeding occur in the present range of distribution of the species. Microsatellite loci showed a strong incidence of failed amplifications, which we attribute to the marked intraspecies variability that hampered the application of these highly specific markers. Our results show important genetic variability at all levels studied, from within populations to between basins, possibly coupled to speciation processes. This variability is attributable to restricted gene flow among populations due to short-distance dispersal of the larvae.     

C-banding karyotype and relationship of the dipodids Allactaga and Jaculus (Mammalia: Rodentia) in Egypt

The C-banding karyotype of the jerboas Allactaga tetradactyla, Jaculus jaculus jaculus, and Jaculus orientalis was described and interspecific relationships were discussed. Despite the conservation of a relatively small amount of C-heterochromatin located at the centromeric region of some chromosomes in all karyotypes, a striking loss of C-heterochromatin was clearly observed in J. orientalis. C-bands were totally absent in 33 of the 48 chromosomes of J. orientalis, compared to only 7 for J.j.jaculus and 11 for A. tetradactyla. The differences in C-banding amongst karyotypes of the three species were attributed either to transformation of heterochromatin into euchromatin or vice versa, deletion of heterochromatic segments resulting from pericentric inversions, or to variation of euchromatin content and its correlation with the chromosome size and arrangement of heterochromatin. The present findings are consistent with the main hypotheses derived from morphological, chromosomal, and biochemical data that the genera Allactaga and Jaculus have independently developed from a common ancestral form and that J. jaculus and J. orientalis are both distinct congeneric species, but revealed that the C-banding karyotypes of both J.j.jaculus and J. orientalis are distantly related to each other. Therefore, it is concluded that the karyotype of J.j.jaculus may be ancestral and that of J. orientalis may have derived from it.     

Genetic differentiation and relationship of the dipodidsAllactaga andJaculus (Mammalia, Rodentia) in Egypt based on protein variation

Genetic differentiation among 14 populations representing all Egyptian dipodid (jerboa) species and subspecies was examined at 25 structural loci and interspecific relationships are discussed. Of the 25 loci, only 3 were monomorphic, with the same allele fixed in all taxa, 9 loci were monomorphic, but demonstrated intertaxon variation, and only 13 loci were polymorphic. The overall mean number of alleles per locus (A) was 1.23 ± 0.02 and the average percentage of polymorphic loci per taxon (P) was 23%. The overall mean of observed heterozygosity (H _o) was found significantly higher than that of expected heterozygosity (He); the overall means per taxon were 0.25 ± 0.017 and 0.085 ± 0.007. Mean levels of genetic identity (I) were 0.970 ± 0.003 among geographic populations, 0.718 ± 0.022 between subspecies, 0.590 ± 0.030 between congeneric species, and 0.368 ± 0.020 between genera. Phenetic analysis of genetic distance matrix produced a phenogram indicating a close association ofJaculus orientalis Erxleben, 1777 toJaculus jaculus (Linnaeus, 1758), particularly to its subspeciesJaculus jaculus butleri (Thomas, 1922), and indicating a distinct affinity between these latter two species andAllactaga tetradactyla (Lichtenstein, 1823). Estimates of genetic divergence demonstrated that J. orientalis appears to have shared a more recent common ancestor withJ. jaculus thanA. tetradactyla. Divergence of these species would have occurred by Miocene (ca 9.6 to 18.7 million years ago). The pattern of relationships of the dipodid species indicated in this study was closely consistent with the hypotheses derived from morphological and chromosomal data.     

Genetic variability and level of differentiation among Brazilian pantanal wood stork populations

The Wood Stork (Mycteria americana) is a colonial wading bird of the tropical and lower subtropical zones. We assessed genetic structure within and among five stork colonies from the Brazilian Pantanal and compared our data with those from North American populations. Samples of 234 individuals were studied using protein electrophoresis to evaluate genetic variability and interpopulation differentiation. Of 22 loci examined, 7 were polymorphic (mean heterozygosity = 0.068). The low Fst value (0.005) indicated little intraspecific variation among breeding colonies. Estimated number of migrants per generation based on private alleles (Nm = 11.3) and on Fst (48.8) suggests high gene flow. Nei's genetic distance values among Pantanal colonies ranged from 0.0001 to 0.0034, demonstrating low genetic divergence among populations. Our data can be explained by supposing high gene flow levels among Pantanal colonies, and between North and South American populations, intermediated by a probable interbreeding population in Central America.     

Allozyme variation in the camaenid tree snails Amphidromus atricallosus (Gould, 1843) and A. inversus (Müller, 1774)

We examined allozyme variation in two camaenid tree snails, Amphidromus atricallosus and A. inversus, across two principal regions of Thailand and from Singapore, plus for A. inversus, one site in peninsular Malaysia. Using horizontal starch gel electrophoresis, 13 allozyme loci (11 polymorphic) were screened for A. atricallosus and 18 (5 polymorphic) for A. inversus. Heterozygosity was higher in A. atricallosus (Hexp=0.018-0.201, mean=0.085) than in A. inversus (Hexp=0-0.023, mean= 0.002). Genetic heterogeneity among samples was higher in A. inversus (Fst=0.965) than in A. atricallosus (Fst=0.781). Within A. atricallosus, populations were more differentiated in southern Thailand (Fst=0.551) than in eastern Thailand (Fst=0.144). The high Fst and low Hexp in populations of A. inversus suggest that this species is likely to have experienced a series of strong bottlenecks, perhaps occurring chiefly on offshore continental-shelf islands. The low Fst values of A. atricallosus in eastern Thailand suggest frequent gene flows among populations in this region. The southern and eastern samples of A. atricallosus exhibited fixed allele differences at four loci and great genetic distance (Nei's D=0.485-0.946), suggesting that these two samples may actually represent, or else be evolving into, separate species.     

Allozyme variation in Anopheles stephensi Liston from Pakistan (Diptera: Culicidae)

Allozyme variability was analyzed at 16 loci in 11 lines of Anopheles stephensi Liston from Pakistan. Six lines were considered as samples from natural populations. For these lines the mean number of alleles was 1.31-1.63, the degree of polymorphism was 0.188-0.375, the observed heterozygosity was 0.065-0.086, and the genetic distance ranged from 0.001 to 0.016. No population-specific alleles were found. Interbreeding was considerable (mean Fit = 0.183). Differences in allele frequencies were due considerable (mean Fit = 0.183). Differences in allele frequencies were due primarily to local inbreeding (Fis greater than Fst at most loci). The Lahore line, reared for more than 20 generations, had more homozygotes than the other lines. A line refractory to Plasmodium falciparum and a genetic sexing line exhibited decreased allozyme variability. The latter line showed reduced staining intensity at 10 loci. Linkage studies are recommended for the following loci with rare alleles: Acp, Gapdh, Icd-1, Icd-2, Mpi, and Pgd.     

Allopolyploid origin and population genetics of the rare orchid Spiranthes diluvialis

The process of becoming and the attributes of being polyploid play a major role in the development and maintenance of genetic variation in allopolyploid species. A genetic survey employing protein electrophoresis on 12 populations of S. diluvialis, as well as on populations of eight congeneric species, was conducted to assess the putative allopolyploid origin of S. diluvialis and to determine the genetic variability within and among populations. Genetic identity values indicated S. diluvialis was more similar to S. magnicamporum (0.619) and S. romanzoffiana (0.727) than to any of the other congeneric species assayed. Similar to most allopolyploids, S. diluvialis showed high levels of fixed, or nearly fixed, heterozygosity and a high percentage of polymorphic loci (57.1-71.4%). The mean number of alleles per polymorphic locus in populations of S. diluvialis (2.6-3.3), however, was similar to mean values for both animal-pollinated, outcrossing, diploid species, and geographically restricted, diploid species (2.6 and 2.5, respectively). Genetic divergence among populations (mean Fst = 0.083) was low, leading to relatively high estimates of interpopulational gene flow (mean Nm = 5.41). Thus, each population harbors most of the genetic variability found within the species. The genetic variation observed within S. diluvialis supports the occurrence of at least two separate hybridization events giving rise to S. diluvialis.