真鲷、黑鲷及其杂交子代的染色体构成与AFLP分析

采用核型分析和AFLP技术对真鲷、黑鲷及其杂交子代进行遗传差异分析。结果显示真鲷、黑鲷和杂交子代均含有48条染色体,核型分别为2n=2st+46t,NF=48、2n=4m+4sm+2st+38t,NF=56和2n=30m+8sm+2st+8t=48,NF=86,杂交子代核型与其父、母本种均不一致。两对AFLP选扩引物组合在真鲷、黑鲷和杂交子代中共扩增到278个条带,其中黑鲷特异性条带93条、真鲷特异性条带108条;杂交子代中分别出现了21条父本种(黑鲷)特异条带和67条母本种(真鲷)特异条带,另出现了15条非双亲条带。杂交子代与真鲷、黑鲷的遗传相似系数和遗传距离分别为0.113、0.350和2.180、1.050,表明杂交子代总体上更偏向于母本种。染色体核型和AFLP条带分析结果表明真鲷(♀)×黑鲷(♂)所获得的杂交子代为含有48条染色体的异源二倍体,且父、母本遗传物质在杂交中发生了部分重组,杂交子代表现出一定的偏母系遗传特性。     

试论沙冬青属的染色体地理*

沙冬青属是我国西北干旱地区及中亚东部荒漠的一个特有属,是我国荒漠中唯一的旱生常绿阔叶灌木,本文采用细胞学的方法,研究沙冬青属2种植物及其近缘属──黄花木属和黄华属在青藏高原的代表种(黄花木、紫花黄华)的核型、酯酶同工酶,进而探讨沙冬青属的演化趋势、地理分布及与环境的关系。本文是植物染色体地理的试验研究。     

Karyotypes of three species of the marine Veneroida molluscs

INTRODUCTIONExceptforcorbiculalivinginfreshwater,themostVeneroidamolluscsliveinthesea .Theyarewidelydistributedwithlargequantityofcategories.Manyofthebivalvemolluscsareculturedfortheireconomicvalue .ThespeciesofSolengrandis,SaxidomuspurpuratusandMactrachinensisareaquaculturedinthenorthernseasofChina .Morphologyandcultivationbiologyofthebivalvemolluschavebeenreported (Qietal.,1 989;Weietal.,1 995;Wangetal .,1 984 ) .Asthefoundationofbivalvemollusccytogenetics ,chromosomestudyiscritical…     

多齿围沙蚕Perinereis nuntia(Savigny,1818)染色体组型

以多齿围沙蚕Perinereis nuntia(Savigny,1818)幼体为材料,研究染色体组型,2n=28,NF=56,其中中部着丝点(m)染色体4对;亚中部着丝点(sm)染色体10对。     

真鲷Pagrosomus major和黑鲷Sparus macrocephalus的核型及Ag—NOR带研究

采用PHA体内注射肾细胞直接制片法及银染法研究真鲷和黑鲷的核型及Ag—NOR带。指出这两种鱼的核型公式分别为2n=48,2st+46t,NF=48和2n=48,4m+4sm+2st+38t,NF=56。两种鱼的核型中各自唯一的一对亚端部着丝点染色体(st染色体)为典型的具次缢痕的染色体。银染结果显示该次缢痕部位即为银染核仁组织者区域(Ag—Nucleolusorganizer regions NORs),并表现出多态性。同时,在这两种鱼的中期分裂相中普遍观察到了NORs联合现象。此外,还讨论了这两种鱼的亲缘关系和鲷科鱼类中两个类群及其核型的分化问题,认为从细胞遗传学角度看,鲷科鱼类的两个类群在演化过程中是分支进化的。     

金虎杂交斑三倍体血细胞特征及染色体核型分析

为了解三倍体金虎杂交斑(棕点石斑鱼Epinephelus fuscoguttatus♀×蓝身大斑石斑鱼E. tukula♂)的细胞遗传特性。以静水压休克诱导的三倍体金虎杂交斑为研究对象,通过细胞DNA含量测定鉴定出三倍体金虎杂交斑、对三倍体金虎杂交斑进行红细胞大小、形态的比较及染色体核型分析。结果显示,三倍体金虎杂交斑的DNA含量与二倍体金虎杂交斑的DNA含量的比值为1.45︰1。三倍体金虎杂交斑血细胞长轴、短轴分别为二倍体的1.34、1.14倍(P<0.01)。三倍体金虎杂交斑血细胞体积、表面积分别为二倍体的2.07和1.54倍(P<0.01),三倍体金虎杂交斑血细胞核长轴、短轴、核表面积、核体积分别为二倍体的1.22、1.05、1.29、1.57倍(P<0.01)。通过头肾-秋水仙素注射法进行染色体核型分析结果显示,二倍体金虎杂交斑的染色体数目为48,核型为2n=48=2sm+46t, NF=50,三倍体金虎杂交斑的染色体数目为72,核型为3n=72=1m+2sm+69t,NF=75,未发现有性染色体。实验结果为石斑鱼杂交种多倍体育种提供了丰富生物学基础数据。     

尾纹裸头 虎鱼染色体组型分析

以尾纹裸头虎鱼的脾脏细胞为材料,用空气干燥法制片,进行其染色体组型分析。染色体数目２ｎ为４４,染色体总臂数（ＮＦ）为８６,其中中部着丝点染色体为１０对,亚中部着丝点染色体为１１对,端部着丝点染色体只１对,即２ｎ等于２０ｍ＋２２ｓｍ＋２ｔ。     

硬壳蛤的核型研究

基于硬壳蛤（Mercenaria mercenaria（Linnaeus,1758））是一种生长速度快、经济效益高的埋栖型双壳类,为给生产提供更多的遗传学理论依据,以硬壳蛤胚胎（4-8细胞期）为材料,通过压片法和空气干燥法进行染色体制片和核型分析。结果表明：硬壳蛤二倍体染色体数目为2n=38,其中中部着丝粒染色体（m）有14对,亚中部着丝粒染色体（sm）有4对,亚端部着丝粒染色体（sr）有1对,无端部着丝粒染色体（r）。核型公式为28m＋8sm＋2st,染色体臂数=74。未发现性染色体和随体。     

Karyological analysis of the sea cicada Blepharipoda liberate Shen from the Rizhao intertidal zone,China

Blepharipoda liberate Shen is a commercially valuable seafood species that has important ecological signi?cance in Shandong Province, China. Although B. liberate is crustacean, its external characteristics are not entirely those of shrimps or crabs. The question of whether B. liberate is a shrimp or a crab has been debated in recent years. We studied the karyotype of B. liberate by light microscopy using air-drying and spreading methods. We obtained mitotic chromosomal plates from B. liberate larvae, and from adult B. liberate females subsequent to egg-laying. The results revealed that B. liberate has 53 pairs of chromosomes(i.e., n =53 and 2 n =106), a characteristic shared with four species of crab. The karyogram of B. liberate consists of 25 metacentric, 14 submetacentric, 11 subtelocentric and 3 telocentric pairs. We did not ?nd any heteromorphosis sex chromosomes. Tissue from larvae, gills and ovaries can be used for chromosomal investigations, and we found similar lampbrush chromosomes in ovary cells. Comparatively speaking, larvae tissue is more practical, and ovary tissue is more suitable for the preparation of lampbrush chromosomes. B. liberate is more closely related to crabs than to shrimps, based on the numbers of chromosomes. The B. liberate karyotype reported here provides a basis for further comparative cytogenetic studies of species populations.     

不同地理种群大黄鱼染色体核型的比较研究

大黄鱼(Pseudosciaena crocea(Richardson)),隶属于鲈形目(Perciformes),石首鱼科(Scieani-dae),黄鱼属(Pseudosciaena),是我国重要的海水养殖种类.近年来,经过长期的人工繁育和人工养殖,大黄鱼的性状有了较大的变化.主要表现为个体小型化,性成熟提前,抗病力下降等.目前有关大黄鱼遗传背景的研究还十分缺乏,相关的研究仅见于国内学者对养殖、野生大黄鱼的染色体核型、同工酶酶谱、不同群体遗传多样性水平的研究[1~7],这些研究多是针对我国沿海3个大黄鱼地理种群之一的闽粤东族进行的.