伴性遗传,限性遗传与从性遗传

伴性遗传、限性遗传与从性遗传殷康俊（安徽省铜陵有色铜山矿中学２４７１２７）伴性遗传（ｓｅｘ－ｌｉｎｋｅｄｉｎｈｅｒｉｔａｎｃｅ）是指性染色体上的基因所控制的性状在遗传方式上与性别相联系。在生物的性状中,还有限性性状和从性性状,这两类性状的遗传分别叫限...     

孟德尔定律的发展与扩充

随着分子遗传学研究的不断深入,遗传学特别是医学遗传学的一些遗传现象,经典的盂德尔式遗传理论不能解释,本文试图介绍这方面的新的进展和成就。     

植物种质群体遗传结构改变的测度

本文旨在探讨植物种质资源保存中由于人为和自然缘故导致遗传结构改变的评价指标和评价方法.在介绍植物种质资源保存研究一些基本概念的基础上,归纳了测度种质库(收集品)遗传潜势的6种遗传多样性统计指标,包括同一变异层次的类型数、类型分布均衡度、遗传相似性与遗传距离、遗传方差与遗传变异系数、多元变异指数以及亲本系数.指出若无遗传丰富度相伴,单有遗传离散度并未提供遗传多样性的完整测度.探讨了人为条件导致植物种质资源遗传结构改变的遗传流失、环境胁迫所致植物种质资源遗传结构改变的遗传脆弱性和种子扩繁所引发的植物种质资源遗传结构改变的遗传漂变和遗传漂移等的统计指标.文末给出了自花授粉植物和异花授粉植物群体适宜样本容量研究的个例.     

应用ISSR-PCR分析蒙古栎种群的遗传多样性

本研究应用ISSR标记技术对东北地区的优势树种蒙古栎（Quercus mongolica）的25个种群遗传多样性进行了分析，目的是为蒙古栎早期选择提供依据。从60条ISSR引物中筛选出10个特异性强、稳定性好的引物进行ISSR分析。共获得位点数71个，其中多态位点数56个，多态位点百分率为78．87％。PopGene分析结果表明：种群的平均多态位点百分率为45．2％，Shannon表型多样性指数（I）平均值为0．25，具有较高的遗传多样性，种群间存在一定程度的基因流（^0为1．3818）和遗传分化（Nei’s信息多样性指数平均值为0．1068，Gst平均值为0．2657），种群内的基因多样度占总种群的73．43％，种群间占26．57％，表明蒙古栎种群的变异主要来源于种群内。结合聚类分析和地理变异规律把种群划分为两个大的种群组：小兴安岭种群组和长白山种群组。以上结果可为栎属种质资源的保护和利用以及物种分化研究提供基础资料。     

遗传教学中关于性染色体的几个问题

遗传教学中关于性染色体的几个问题李训仕（湖北省黄冈师范专科学校生物系４３６１００）性别是生物界中普遍存在的一种生物性状,与遗传有着直接的联系。自１９０１年ＭｃＣｌｕｎｇ在直翅目昆虫中首次发现性染色体后,就自然地把性别决定与性染色体联系起来。性染色体是...     

不同环境下籼稻糙米重的发育遗传研究

采用包括遗传主效应和基因型与环境互作效应的数量性状发育遗传模型和统计分析方法 ,分析了籼稻(OryzasativaL .)稻米 4个发育时期糙米重的两年资料。结果表明 ,除了三倍体胚乳和二倍体母体植株基因的加性和显性主效应以及细胞质主效应可以控制不同稻米发育时期的糙米重量外 ,基因型与环境互作效应也可明显影响不同发育时期糙米重量。基因加性主效应和加性×环境互作效应在整个稻米灌浆过程中起着主要作用 ,对糙米重的选择可以取得良好的改良效果。条件方差分量分析结果表明 ,胚乳和母体植株中控制糙米重表现的基因在多数稻米发育时期均有新的表达 ,且以稻米发育早期为主 ,开花后第 1～ 7天是控制糙米重的基因表达最为活跃的时期 ,其次为开花后第 8～ 14天。一些基因只在个别发育时期间断表达 ,这在净细胞质主效应和净细胞质×环境互作效应以及净显性主效应上表现得尤为明显。稻米不同发育时期的遗传效应预测值表明 ,V2 0和作 5等亲本可以明显提高后代的糙米重量。     

花楸树天然群体的遗传多样性研究

花楸树(Sorbus pohuashanensis)是我国北方一种观赏兼经济用途的树种。本研究采用水平淀粉凝胶同工酶电泳技术, 对采自山东、山西、河北、辽宁4个省的8个花楸树天然群体的种子样本进行了分析, 旨在了解花楸树天然群体的遗传多样性和遗传结构, 为该树种的保护与利用提供科学依据。4个酶系统10个位点的检测结果表明, 花楸树群体水平上的遗传多样性较高, 每位点平均等位基因数(N_a)为2.2000, 多态位点百分率(P)为100%, 期望杂合度(H_e)为0.4240。花楸树8个群体间的有效等位基因数(N_e)、H_e和Shannon信息指数差异较小，3个指标从高到低依次为: 河北驼梁山＞河北雾灵山＞山西庞泉沟＞河北白石山＞山东崂山＞河北塞罕坝＞山东泰山＞辽宁老秃顶子。群体间遗传分化系数(F_st)为0.0758, 群体间总的基因流较高(N_m = 3.0472), 群体间遗传一致度较高(I为0.8585– 0.9872), 表明群体间遗传分化程度小。在单个群体中, 通过χ2检验, 花楸树群体有73.62%的位点组合显著偏离Hardy-Weinberg平衡(P＜0.05), 总群体水平近交系数(F_it)和单个群体水平近交系数(F_is)分别为–0.3105和–0.4180, 表明无论在总体水平还是群体内个体间, 花楸树群体表现为杂合体过量的现象。UPGMA聚类结果显示, 8个群体的遗传距离与地理距离相关性不显著。     

iPS细胞的遗传安全性

自2006年Takahashi和Yamanaka首次成功地从小鼠成纤维细胞诱导得到诱导多能性干细胞(Induced pluripotent stem cells,iPS细胞)以来,iPS细胞由于其潜在的广阔应用前景而迅速成为干细胞研究领域的新热点;与此同时,iPS细胞的遗传安全性也越来越多地受到人们的关注。文章将对iPS细胞遗传安全性的研究进展进行综述,分析造成iPS细胞遗传不稳定的可能原因,希望可以促进对iPS细胞诱导条件的优化,获得遗传上较为安全的iPS细胞。     

RAPD技术及其在动物遗传育种中的应用

ＲＡＰＤ技术是在ＰＣＲ基础上发展起来的一种ＤＮＡ多态性检测技术,已广泛应用于基因组研究的种个领域。本文概述了ＲＡＰＤ反应的原理、特点,总结了其在遗传多样性检测、亲缘关系鉴定、遗传连锁分析和数量性状的辅助标记选择等方面的应用,并肯定了ＲＡＰＤ在动物遗传户种领域的应用前景。     

SSR在琼海和三亚两普通野生稻居群中的遗传变异

通过分析37个SSR座位在琼海与三亚两普通野生稻（Oryza rufipogon）居群中的遗传变异,结果表明,SSR座位在三亚普通野生稻居群中的变异高于其在琼海普通野生稻居群中的变异。根据遗传相似性和遗传距离公式得到琼海与三亚普通野生稻居群间的遗传相似性为0．6385,遗传距离为0．4486cM。Wright的啪验结果表明,这37个SSR座位在两居群之间存在着中等程度的遗传分化,FST=0．3909。此分化结果主要是由两居群间弱的基因漂移导致的（Nm=0．3895）。     

The Statistical Properties of Genetic Absolute Distance

The statistical properties of one estimator of absolute genetic distance (1/2) ^K∑_i=1 |pxi-yr|, tween two populations X and Y, are presented. It is shown that using this distance in small samples can be misleading particularly when populations are close to each other.     

Prediction of genetic gain from quadratic optimisation with constrained rates of inbreeding

There are selection methods available that allow the optimisation of genetic contributions of selection candidates for maximising the rate of genetic gain while restricting the rate of inbreeding. These methods imply selection on quadratic indices as the selection merit of a particular individual is a quadratic function of its estimated breeding value. This study provides deterministic predictions of genetic gain from selection on quadratic indices for a given set of resources (the number of candidates), heritability, and target rate of inbreeding. The rate of gain was obtained as a function of the accuracy of the Mendelian sampling term at the time of convergence of long-term contributions of selected candidates and the theoretical ideal rate of gain for a given rate of inbreeding after an exact allocation of long-term contributions to Mendelian sampling terms. The expected benefits from quadratic indices over traditional linear indices (i.e. truncation selection), both using BLUP breeding values, were quantified. The results clearly indicate higher gains from quadratic optimisation than from truncation selection. With constant rate of inbreeding and number of candidates, the benefits were generally largest for intermediate heritabilities but evident over the entire range. The advantage of quadratic indices was not highly sensitive to the rate of inbreeding for the constraints considered.     

桃不同类群的遗传多样性及其遗传结构的RAPD分析

采用RAPD技术,利用从200个随机引物筛选的22个十碱基引物对桃10个类群180个样品的DNA进行扩增,得到180个位点。通过对所得的数据统计分析,在类群的遗传多样度上表现为:黄肉桃类>蜜桃类>蟠桃类>红叶桃类>硬肉桃类>碧桃类>水蜜桃类>油桃类>寿星桃类>垂枝桃类。在180个位点中检验出多样度范围在0.4以上的位点分布在桃总群体中的有37个,而在桃类群间的则有13个。聚类分析的结果是:桃食用栽培品种的类群聚为一组;其它非食用桃类群各为一组。对桃类群的遗传多样性及其结构分析,为桃的品种资源保存和利用提供分子生物学依据。     

作物品种间杂种优势遗传分析的新方法

本文提出了分析双列杂交试验资料的两个遗传模型。第一个模型包括加性、显性和母体效应;第二个模型只包括简单的加性和显性效应。还介绍了分析杂种优势、估算遗传方差分量以及预测遗传效应值的相应统计分析方法。用所介绍的遗传模型和分析方法以及常用的Griffing配合力分析方法,分析了棉花6个品种双列杂交的产量性状,并进一步比较了不同方法的分析结果。采用本文所介绍的遗传模型和分析方法,可以克服用Griffing的配合力模型及其方法分析杂种优势和配合力遗传表现所存在的局限性。     

Evolutionary potential of Chamaecrista fasciculata in relation to climate change. II. Genetic architecture of three populations reciprocally planted along an environmental gradient in the great plains

Climate change will test the evolutionary potential of populations. Information regarding the genetic architecture within and among populations is essential for prediction of evolutionary outcomes. However, little is known about the distribution of genetic variation for relevant traits in natural populations or alteration of genetic architecture in a changing environment. In this study, pedigreed families from three populations of the annual prairie legume Chamaecrista fasciculata were reciprocally transplanted in three environments across a broad latitudinal range in the Great Plains. The underlying premise of this work is that northern populations will in the future experience climates similar to current-day climates further south. Estimates of narrow-sense heritability ranged from 0.053 to 0.481, suggesting the potential for evolutionary change is possible for most traits. In general, the northern population harbored less genetic variation and had lower heritability for traits than the southern population. This population also experienced large reductions in fitness, as measured by estimated lifetime fecundity, when raised in either the intermediate or the southern climate, whereas the difference between the intermediate and southern population was less extreme. For fecundity, the pattern of cross-environment additive genetic correlations was antagonistic to evolutionary change in four of six cases when native and nonnative sites were compared. Six additional antagonistic positive correlations were found for the rate of phenological development and leaf thickness. Overall, the data suggest that if climate changes as predicted, the northern population will face a severe evolutionary challenge in the future because of low heritabilities, cross-environment genetic correlations antagonistic to selection, and demographic instability due to lower seed production in a hotter and drier climate.     

昆虫种群的遗传调控

昆虫种群的遗传调控是利用昆虫自身生长发育的关键基因,采用性别控制开关,通过遗传转化使雄虫成为携带导致后代雌虫发育异常或雌性不育的遗传控制复合体（性别开关元件和靶标基因的复合体）．昆虫种群遗传调控是一种基于不育技术的昆虫种群控制系统,具有种类特异、环境友好和便捷高效等特点．目前为止,已经由早期的通过辐射不育方法发展到释放携带显性致死基因昆虫的方法,并在多种昆虫中获得成功．本文综述了昆虫种群遗传调控的发展历程,介绍了昆虫种群遗传调控相关的理论与方法,包括特异的调控元件、致死或缺陷基因和遗传转化体系的应用,并列举了几种昆虫种群遗传调控的实例,最后对于昆虫种群遗传调控系统中存在的问题以及可能的发展方向进行了展望．     

Origins of gene, genetic code, protein and life: comprehensive view of life systems from a GNC-SNS primitive genetic code hypothesis

We have investigated the origin of genes, the genetic code, proteins and life using six indices (hydropathy, α-helix, β-sheet and β-turn formabilities, acidic amino acid content and basic amino acid content) necessary for appropriate three-dimensional structure formation of globular proteins. From the analysis of microbial genes, we have concluded that newly-born genes are products of nonstop frames (NSF) on antisense strands of microbial GC-rich genes [GC-NSF(a)] and from SNS repeating sequences [(SNS)_n] similar to the GC-NSF(a) (S and N mean G or C and either of four bases, respectively). We have also proposed that the universal genetic code used by most organisms on the earth presently could be derived from a GNC-SNS primitive genetic code. We have further presented the [GADV]-protein world hypothesis of the origin of life as well as a hypothesis of protein production, suggesting that proteins were originally produced by random peptide formation of amino acids restricted in specific amino acid compositions termed as GNC-, SNS and GC-NSF(a)-0th order structures of proteins. The [GADV]-protein world hypothesis is primarily derived from the GNC-primitive genetic code hypothesis. It is also expected that basic properties of extant genes and proteins could be revealed by considerations based on the scenario with four stages This review is a modified English version of the paper, which was written in Japanese and published inViva Origino 2001 29 66–85.     

Effects of forced migrations on spatial and temporal changes in genetic structure of two local populations in Bosnia

Ten qualitative traits were observed in two isolated human populations in Bosnia for prewar and postwar periods. Due to recent war in Bosnia and Herzegovina two million citizens was forced to migrate. Dramatic migration effects occurred in the investigated populations. Population characteristics found were geographic isolation, high levels of marital distance “zero”, patrilocality and propagation isolation. Relative recessive allele frequencies of ten qualitative traits were calculated. Average heterozigosity, genetic differentiation, total heterozigosity, within populations heterozigosity, genetic distance and relative measures based on results of genetic distance analysis were observed. The total number of observed individuals was 1875. We have observed 1209 individuals in prewar period (Bijela population 731 and Memici population 478) and 666 individuals in the postwar period (Bijela population 248 and Memici population 478). Results ofFst andGst analysis showed changed degree of genetic differentiation across observed loci. Significant changes in differentiation were recorded for crooked little finger and PTC tasting. Modest changes of gene differentiation were recorded for ear lobe type and thumb proximal extensibility. Genetic distance analisis between Bijela and Memici has lower value after then before the war, but genetic distance between Bijela-prewar and Bijela-postwar has higher value, as well as Memici-prewar and Memici-postwar genetic distance. Genetic distance between Bijela-prewar and Memiciprewar, as well as Bijela-postwar and Memici-postwar showed similarity. Constructed dendrogram based on results of genetic distance analyses indicated two clusters groups (1. Bijela-prewar, Memici-prewar; 2. Bijela-postwar, Memici-postwar). Changed genetic differentiation and results of genetic distance analyses indicated possibility of significant impact of forced migration in genetic structure of observed populations.     

Forward from the crossroads of ecology and evolution

Community genetics is a synthesis of community ecology and evolutionary biology. It examines how genetic variation within a species affects interactions among species to change ecological community structure and diversity. The use of community genetics approaches has greatly expanded in recent years and the evidence for ecological effects of genetic diversity is growing. The goal of current community genetics research is to determine the circumstances in which, and the mechanisms by which community genetic effects occur and is the focus of the papers in this special issue. We bring a new group of researchers into the community genetics fold. Using a mixture of empirical research, literature reviews and theoretical development, we introduce novel concepts and methods that we hope will enable us to develop community genetics into the future.     

The probability of genetic parallelism and convergence in natural populations

Genomic and genetic methods allow investigation of how frequently the same genes are used by different populations during adaptive evolution, yielding insights into the predictability of evolution at the genetic level. We estimated the probability of gene reuse in parallel and convergent phenotypic evolution in nature using data from published studies. The estimates are surprisingly high, with mean probabilities of 0.32 for genetic mapping studies and 0.55 for candidate gene studies. The probability declines with increasing age of the common ancestor of compared taxa, from about 0.8 for young nodes to 0.1–0.4 for the oldest nodes in our study. Probability of gene reuse is higher when populations begin from the same ancestor (genetic parallelism) than when they begin from divergent ancestors (genetic convergence). Our estimates are broadly consistent with genomic estimates of gene reuse during repeated adaptation to similar environments, but most genomic studies lack data on phenotypic traits affected. Frequent reuse of the same genes during repeated phenotypic evolution suggests that strong biases and constraints affect adaptive evolution, resulting in changes at a relatively small subset of available genes. Declines in the probability of gene reuse with increasing age suggest that these biases diverge with time.