“全红”瓯江彩鲤不同世代间的遗传结构及遗传分化初步分析

利用ISSR技术对"全红"瓯江彩鲤(Cyprinus car pio var. color)4个世代群体的遗传结构及其分化进行了分析。筛选的15个ISSR引物从4个世代群体中分别扩增到120、118、101和110条扩增谱带,全部扩增片段长度在200—2500bp之间。根据扩增结果,利用POPGENE version 1.31进行分析,结果表明:4个群体的多态位点比例(P)为51.49%—67.80%,Shannon信息指数(Ho)为0.2176—0.2745之间,并随着世代的增加,选育群体的遗传多样性呈现下降趋势。有70%的遗传变异来自于群体内;结合遗传分化指数Gst、UPGMA聚类分析,证实"全红"瓯江彩鲤4个世代间存在一定程度的遗传分化,即任意两个群体间的遗传分化达到较大的水平(Gst均为0.1588—0.2766)。     

草鱼种质相关SRAP及SCAR的分子标记

采用相关序列扩增多态性(Sequence-realted Amplified Polymorphism, SRAP)技术分析野生草鱼和家养草鱼,筛选与草鱼种质退化相关的分子遗传标记.共进行88对引物组合的检测, 产生标记数目共计905个.依据标记在群体中出现的频率和变化规律,共筛选出2 1个可能与种质相关的特异性标记,对这些特异性标记进行测序并将测序结果进行BLAST分析 .发现测得片段中有8个片段在GenBank中找到同源性较高的序列,而其他片段与数据库中序列的相似性较低.根据序列信息分别设计了3对引物.用这3对引物分别对草鱼三个群体进行 PCR扩增,分别产生了SCAR1(308 bp)、SCAR2(66 bp)、SCAR3(114 bp)3个扩增带.采用大样本对这3个标记进行验证,发现其中SCAR1在家养群体中呈现阳性,在野生群体中为阴性,可区分出这两种群体.以SCAR3为引物在174条家养群体中得到目的片段,在26个家养群体没有扩增出条带,分布频率为87%;在100个野生群体中有6个个体检测到该条带,分布频率为6%.以SCAR2为引物在野生群体中完全扩增出目的条带,淡水中心群体中有7条扩增到条带,前洲群体中没有扩增出条带,标记在家养种群中的分布频率为96.50%.因此SCAR1可作为草鱼家养群体的一个重要的分子遗传特征指标,为进一步进行分子标记辅助育种奠定了基础 [动物学报 54(3):475-481,2008].     

SRAP技术在遗传的研究进展

SRAP是一种新型的DNA分子标记,具有简便、稳定、中等产率和容易得到选择条带序列的特点。SRAP利用独特的引物设计对开放读码框(ORFs)进行扩增,上游引物长17bp,对外显子进行特异扩增,下游引物长18bp,对内含子区域、启动子区域进行特异扩增,因个体不同及其物种的内含子、启动子与间隔长度不等而产生多态性。本文阐述SRAP的原理和操作流程,综述了SRAP标记目前在植物遗传图谱构建、遗传多样性、基因定位、基因克隆、杂种优势利用等方面的研究进展及应用前景。     

甜瓜抗白粉病基因SRAP分子标记筛选

以感白粉病甜瓜A120和抗白粉病甜瓜A119为亲本构建F2代分离群体,采用BSA和SRAP相结合的方法筛选与甜瓜抗白粉病基因相连锁的分子标记.结果显示,294条SRAP引物中有6条引物在抗病与感病池间表现出多态性;对8个高抗和8个高感单株进行扩增,引物me46em51和me3em6分别在高感单株中扩增出210 bp和205 bp的多态性条带,而高抗单株无此扩增带,与抗病、感病池结果一致.采用JoinMap3.0软件进行连锁分析,两标记与抗白粉病基因的连锁距离分别为18.2 cM和23.4 cM,初步推测本实验中甜瓜白粉病抗性为隐性多基因控制.     

耐盐绒毛白蜡特异性SCAR分子标记的鉴定

该研究以耐盐型和盐敏感型绒毛白蜡及其F1代为材料,采用混合品系分析法进行RAPD分析。结果显示:在随机选取的150个10碱基随机引物中,仅有引物S20在耐盐基因池和盐敏感基因池间扩增出特异而可重复的592bp的多态性片段,命名为S20-592。获得的RAPD标记S20-592经克隆、测序、重新设计一对特异性引物转化成更稳定的SCAR标记。通过F1代个体验证,耐盐型个体均能扩增出此差异条带而盐敏感型个体中不能扩增出此差异条带,证明该SCAR标记的特异引物可用于耐盐绒毛白蜡物种的快速分子鉴定。     

陆地棉HB红花性状特异SCAR分子标记的开发

利用Operon系列引物筛选到1个与HB红花性状基因连锁的RAPD标记OPA15^1160,对差异条带进行克隆与核苷酸测序,根据测序结果设计SCAR引物,在HB红花近等基因系及其白花轮回亲本中进行PCR扩增程序优化和鉴定,筛选出一对引物可稳定扩增出与HB红花性状基因连锁的特异片段,获得了与HB红花性状基因紧密连锁的SCAR标记HB^-330。利用具黄色花瓣紫红色基斑的海岛棉与粉红花瓣的红叶棉等种质材料以7LHB红花近等基因系与白花轮回亲本杂交的F1、BC1F1、F2群体,对该SCAR标记的特异性与准确性进行了鉴定与验证,在红花植株中扩增出了330bp大小的片段而在白花植株中未扩增出,证明该标记准确性高、重复性好。HB红花是通过远缘杂交转自野生二倍体比克氏棉的性状,已成功地应用于性状标记杂交棉育种。该SCAR标记不仅为HB红花标记杂交种的纯度鉴定提供了有效技术手段,也为新品种保护提供了技术支持,促进了红花性状杂交种的分子标记辅助育种进程。     

新型标记SRAP在棉花F2分离群体及遗传多样性评价中的适用性分析

将新型分子标记SRAP(Sequence-related Amplified Polymorphism)应用于棉花的遗传研究,并建立了完整的PCR反应体系,此体系稳定可靠、扩增效果好、可重复性强。采用30个SRAP引物组合对海岛棉品种“Pima90”和陆地棉品种“邯郸208”进行比较扩增,29个引物组合可以获得多态性扩增,显示了较高的多态性。对上述两个品种的F2群体进行检测,共产生149个多态性条带,平均每个组合产生5．14个,单引物组合最多可产生13个多态性条带。用SRAP标记对11份陆地棉材料进行遗传多样性检测,30个引物组合中15个组合有多态性,得到22个多态性条带,显示了较高的多态性比率。研究结果表明,SRAP标记可在棉花分子生物学领域中广泛应用。     

棉花遗传多样性SCoT和SRAP标记的研究及比较分析

利用SCoT和SRAP两种分子标记技术对30份彩色棉与白色棉种质资源,进行遗传多样性研究。用29对SRAP引物组合和26个SCoT引物分别对供试棉花的基因组DNA进行扩增。SCoT引物共扩增出163条带,多态性比率为61.96%,遗传相似系数GS值变化范围为0.5405～0.9972。SRAP引物组合共扩增条带1067条,多态性比率仅为14.1%,遗传相似系数GS值变化范围为0.5415～0.9109。两种标记系统得到了相似但并不完全相同的聚类图,2种标记方法间存在显著相关性(r=0.5518,P<0.05)。结果表明,SRAP与SCoT标记均适用于棉花种质的遗传多样性分析,且SCoT的标记指数MI高于SRAP标记,为SCoT这种新兴的标记技术在棉花育种中的应用提供了重要的依据。     

美洲黑杨遗传差异的SRAP和EST-SSR分析

采用SRAP和EST-SSR分子标记对美洲黑杨I-69及与其有亲缘关系的4个美洲黑杨品种进行遗传差异分析,比较两种分子标记在遗传差异性分析中的适用性,为美洲黑杨的鉴别提供准确的分子技术依据。结果表明:(1)以SRAP标记筛选出21对引物组合,共扩增出287条谱带,多态性条带209条,多态性比率72.8%,遗传相似系数为0.548 1~0.769 2。(2)以EST-SSR标记筛选出17对引物,共扩增出86条谱带,多态性条带69条,多态性比率80.2%,遗传相似系数为0.444 4~0.717 2。(3)对SRAP和EST-SSR以及两者混合数据形成的3个遗传相似矩阵进行相关性分析结果显示,SRAP和EST-SSR分别同综合数据之间呈显著相关(r=0.844 2,r=0.830 8)。(4)聚类分析发现,两种分子标记的聚类结果有一定差异,SRAP聚类结果同综合数据分析的结果一致,说明SRAP标记更适用于杨树亲缘关系较近材料的遗传差异分析。     

冬枣×宁梨巨枣的子代SRAP鉴定及遗传多样性分析

应用SRAP分子标记方法对冬枣×宁梨巨枣的子代进行了分子鉴定及遗传多样性分析。采用构建基因池的方法对SRAP分子标记引物进行筛选,从88对引物中筛选出15对多态性好、主带清晰的引物,并对子代进行了真实性鉴定及多态性分析。结果表明:(1)15对引物共产生95个多态性条带,平均每对引物产生6.3个多态性条带,显示了较高的多态性比率。(2)80个子代中44个具有父本特征带,鉴定为真杂种。子代遗传多样性及UPGMA聚类分析表明,子代个体与亲本间的遗传相似系数在0.55~0.98之间,个体差异明显。该研究结果为枣树杂交育种提供了重要的分子证据。     

豹纹鳃棘鲈体色变异的色素细胞差异分析

为了揭示豹纹鳃棘鲈(Plectropomus leopardus)体色变异机制, 研究选取了不同体色个体的样本, 利用石蜡切片、冰冻切片及体视显微镜观察等方法揭示不同皮肤部位色素细胞的类型、分布和数量的差异, 并对应激和非应激状态下色素细胞的变化进行了研究。结果显示, 黑色素细胞在背部和尾部分布比较密集, 在腹部较为稀疏, 黑色个体的黑色素细胞数量较红色个体多; 在应激状态下个体能迅速发生体色变化, 主要由于色素细胞快速扩张和收缩导致。研究为进一步揭示豹纹鳃棘鲈体色变异的分子机制和优良品种选育奠定了基础。     

BUTTERFLY EYESPOTS: THE GENETICS AND DEVELOPMENT OF THE COLOR RINGS

The butterfly Bicyclus anynana has a series of distal eyespots on its wings. Each eyespot is composed of a white pupil, a black disc, and a gold outer ring. We applied artificial selection to the large dorsal eyespot on the forewing to produce a line with the gold ring reduced or absent (BLACK) and another line with a reduced black disc and a broad gold ring (GOLD). High heritabilities, coupled with a rapid response to selection, produced two lines of butterflies with very different phenotypes. Other eyespots showed a correlated change in the proportion of their color rings. Surgical experiments were performed on pupal wings from the different lines at the time of eyespot pattern specification. They showed that the additive genetic variance for this trait was in the response of the wing epidermis to signaling from the organizing cells at the eyespot center (the focus). This response was found to vary across different regions of the wing and also between the sexes. The particular eyespot color composition found for each sex, as well as the maintenance of the high genetic variation, are discussed with reference to the ecology of the butterfly, sexual selection, and visual selection by predators.     

GENETIC BASIS AND EVOLUTIONARY SIGNIFICANCE OF VENTRAL SKIN COLOR MARKINGS IN NORTH ATLANTIC RIGHT WHALES (EUBALAENA GLACIALIS)

Approximately one third of the North Atlantic right whale population has white ventral skin patches. Most white-marked animals have both a belly and a chin patch, and the distribution of white pigment suggests that the patches represent a single ventral marking that varies in size and location. Population frequencies and cow-calf inheritance patterns indicate that the white mark is an autosomal recessive trait. There is no evidence to suggest that ventral coloration patterns are currently under selection. White-marked and black cows appear to experience similar levels of reproductive success based on calving intervals and length of sighting histories. Also, white-marked animals were equally common among cows and nulliparous adult females and among live vs. dead animals. Male reproductive success could not be tested because calf paternity is not known; white-marked and black males exhibit similar survival rates. White-marked cows were more common among females that took some or all of their calves to the Bay of Fundy summer nursery area compared to females that did not visit Fundy. This suggests that female habitat-use patterns may influence nuclear gene flow. Increased sample sizes and additional markers are needed to further investigate gene flow.     

THE DARK ADAPTATION OF THE COLOR ANOMALOUS MEASURED WITH LIGHTS OF DIFFERENT HUES

Determinations of minimum light thresholds as a function of time in the dark have been made for four color normal, three deuteranopic (or deuteranomalous), and four protanopic (or protanomalous) subjects. Measurements were made with red, reddish orange, yellow, green, violet, and white test lights. Dark adaptation curves for the deuteranopes and deuteranomalous are essentially identical with those of the color normal for all colors. The cone portions of the protanopic dark adaptation curves measured with the red, reddish orange, yellow, and white lights are higher than the corresponding data for the color normal, the discrepancy between the two sets of data decreasing from the long to short wave lengths. Dark adaptation curves for the protanopes and protanomalous measured with green and violet light are essentially normal in appearance. A theoretical explanation is advanced to account for these findings in terms of the known sensitivity characteristics of the normal and color-anomalous eye.     

锦鲤总色素及色素组分的比较研究

用光谱和色谱两种方法对锦鲤的总色素和色素组分进行了研究。研究结果表明,红色锦鲤、乌鲤和绯写锦鲤总色素光谱在可见光区(448nm和470nm)有两个完全相同的吸收峰,黄写锦鲤和昭和三色锦鲤总色素光谱在可见光区(445nm和472nm附近)有两个相近的吸收峰,锦鲤所含色素组分均以杏黄色或橙色为主,其他色素组分为辅。锦鲤黑色色斑是由于黑色素存在时,其他各色素组分的颜色被黑色所掩盖;锦鲤其他色斑的形成则是由于其体内各色素组分以不同比例相互搭配组合的结果。亲缘关系越近的锦鲤其总色素组分就越相似,红色锦鲤和乌鲤均含有六种相同的色素组分,绯写锦鲤除杏黄色和橙色色素组分与前二者的同色色素组分Rf值不同外,其余四种同色色素组分的Rf值均相近;黄写锦鲤与昭和三色锦鲤分别含有三种和四种色素组分且Rf值差异显著。据此推测,红色锦鲤、乌鲤和绯写锦鲤可能具有较近的亲缘关系,而黄写锦鲤、昭和三色锦鲤与前三者之间可能具有较远的亲缘关系。该研究有望为锦鲤增色饵料的研制与开发提供理论依据,使锦鲤的观赏价值和经济价值得到进一步提高。       

POSTZYGOTIC GENETIC INCOMPATIBILITY BETWEEN SYMPATRIC COLOR MORPHS

Alternative genetically determined color morphs within a population or species are believed to successfully interbreed within a population. However, the occurrence of prezygotic or ecological selection in a number of polymorphic systems may lead to nonrandom mating and prevent genetic morphs from fully interbreeding. Here we show that postzygotic incompatibility significantly limits gene flow between the sympatric red and black color morphs of the Gouldian finch ( Erythrura gouldiae ). Using a balanced within-female experimental design, in which individuals were forced to breed in pure and mixed morph crosses, we found large inviability effects (>30%) in offspring resulting from genetically mixed genotypes. The consistent mortality effects across different stages of development (e.g., prehatching, juvenile, adulthood), unconfounded by environmentally derived parental effects or social environments, reveal an underlying genetic incompatibility between different genotypes. Furthermore, mortality in mixed morph genotypes was particularly severe (43.6%) for the heterogametic sex (daughters), which is consistent with Haldane's rule predicted for postzygotic incompatibilities between hybridizing species. This significant, but incomplete, postzygotic isolation suggests that the sympatric morphs may represent transient stages in the speciation–hybridization process.     

LOSS OF NUPTIAL COLOR IN THREESPINE STICKLEBACKS (GASTEROSTEUS ACULEATUS)

Loss of conspicuous nuptial color in Gasterosteus aculeatus (threespine stickleback) has been reported from several localities in western North America and is ascribed to increased rates of predation or to convergent threat displays. I have examined 66 populations of G. aculeatus from the Queen Charlotte Archipelago and found extensive variation in the expression of red nuptial color. Males in 31 of the populations lack red throats, while males in five populations have major expression of red nuptial color. I test two hypotheses for nuptial-color loss: that the loss results from increased predation rates and that it involves differences in water spectra (relative transmission at 400 nm). Results, which are consistent with the second hypothesis, show that the greatest expression of red pigment occurs in habitats with the highest water clarity, while loss of red nuptial color is generally found in heavily stained waters. There is no correlation between nuptial-color loss and presence or absence of vertebrate predators. Two new hypotheses for these associations are proposed: signal-masking in spectrally restricted habitats and carotenoid deficiencies in the diet. Previous studies of red nuptial color and its loss in Gasterosteus merit additional attention, given the associations with underwater spectra.     

A new species of trout from the northern drainages of Euphrates River,Turkey (Salmoniformes: Salmonidae)

Salmo fahrettini, a new species, is distributed in the northern tributaries of the Euphrates River. It differs from other Salmo species in adjacent waters by a combination of the following characters: a greyish body; one black spot behind the eye and on the cheek; three to six black spots on the opercle; numerous black spots on the back (missing on the predorsal area), flank and middle part of body, surrounded by a roundish white ring; red spots in the median part of the body, surrounded by a roundish white ring; short and narrow maxilla; increase in the number of black and red spots with an increase in size; adipose fin medium size, no or rarely one red spot at its posterior edge; 109–116 lateral line scales; 27–30 scale rows between dorsal-fin origin and lateral line; 20–23 scale rows between the lateral line and anal-fin origin; maxilla length 8.8–10.0% standard length in males, 8.8–9.6 in females.