Preparation and analysis of spermatocyte meiotic pachytene bivalents of pigs for gene mapping

Well-spread meiotic pachytene bivalents were obtained by using the prolonged hypotonic treatment com-bined with high chloroform Carnory’s fixative solution from cells of the testes of domestic pigs. Comparison in the division index and length of pachytene bivalents with metaphase chromosomes showed that those of the former are 5 times higher and 3.42(1.87-5.98) times longer than those of the latter. Comparative studies on chromomere maps of bivalents and mitotic chromosomal G-bands were conducted by using the chromo-some 12 as a example. Sex vesicle and various shapes of synaptic sex chromosomes have been observed.Two-color PRimed IN Situ (PRINS) labeling has been conducted successfully on pachytene bivalents of pigs.     

Preparation and analysis of spermatocyte meiotic pachytene bivalents of pigs for gene mapping

Well-spread meiotic pachytene bivalents were obtained by using the prolonged hypotonic treatment combined with high chloroform Carnory's fixative solution from cells of the testes of domestic pigs. Comparison in the division index and length of pachytene bivalents with metaphase chromosomes showed that those of the former are 5 times higher and 3.42(1.87-5.98) times longer than those of the latter. Comparative studies on chromomere maps of bivalents and mitotic chromosomal G-bands were conducted by using the chromosome 12 as a example. Sex vesicle and various shapes of synaptic sex chromosomes have been observed. Two-color PRimed IN Situ (PRINS) labeling has been conducted successfully on pachytene bivalents of pigs.     

Preparation and analysis of spermatocyte meiotic pachytene bivalents of pigs for gene mapping

Well-spread meiotic pachytene bivalents were obtained by using the prolonged hypotonic treatment com-bined with high chloroform Carnory‘s fixative solution from cells of the testes of domestic pigs. Comparisonin the division index and length of pachytenc bivalents with metaphase chromosomes showed that those ofthe former are 5 times higher and 3.42(1.87-5.98) times longer than those of the latter. Comparative studieson chromomere maps of bivalents and mitotic chromosomal G-bands were conducted by using the chromo-some 12 as a example. Sex vesicle and various shapes of synaptic sex chromosomes have been observed.Two-color PRimed IN Situ (PRINS) labeling has been conducted successfully on pachytene bivalents of pigs.     

家猪减数分裂粗线期二价体与有丝分裂中期染色体的比较研究

以性成熟公猪睾丸和外周血为材料,采用长低渗、高氯仿卡诺固定液固定和外周血细胞培养制备减数分裂粗线期二价体和有丝分裂中期染色体,通过对二价体和有丝分裂中期染色体分裂指数和长度的比较研究,发现二价体的分裂指数和长度分别是有丝分裂中期染色体的5倍和3．42倍（1．87～5．98）;同时以12号染色体为例,比较了二价体上的染色粒结构带与有丝分裂中期染色体G－带,表明染色粒结构带比中期染色体G－带纹丰富,而与早中期G－带带织吻合。     

金线蛙染色体G显带的方法学探索

采用自然老化、氯仿处理及EDTA显带法,首次在金线蛙（R.plancyt）有丝分裂中期染色体上成功显示出G带,带纹反差强烈、特征鲜明。比较了多个来自同一分裂相的同源染色体和不同分裂相的4条大染色体,发现其特征带纹高度一致,带纹数目基本吻合。该方法经济简便,结果稳定可靠。探讨了G显带的可能机制,对进一步开展金线蛙等两栖类的细胞遗传学研究具有一定的参考价值。 Explore on the Advanced Method of G-banding of Rana Plancyt QIAN Shui-ming,YU Qi-xing College of Life Sciences,Wuhan University,Wuhan 430072,China Abstract:Using the technique of natural aging,chloroform and EDTA treatment,well-resolved G-banding patterns were successfully obtained in Rana plancyt's mitosis chromosome firstly.The G-banding patterns appeared distinctive.When analyzing some homologous chromosomes from the same metaphase figures and four macrochromosomes from different metaphase figures,the characteristic and the number of the bands were well matched.The method in this study is also economic and simple and the result is stable and reliable.The possible mechanism of G-banding was primarily discussed.The application of this method in the cytogenetics research of Rana plancyt and other amphibians is expected. Key words：Rana plancyt; mitosis; G-banding     

Cytogenetic comparisons between A and G genomes in Oryza using genomic in situ hybridization

The genomic structures of Oryza sativa （A genome） and O. meyeriana （G genome） were comparatively studied using bicolor genomic in situ hybridization （GISH）. GISH was clearly able to discriminate between the chromosomes of O. sativa and O. meyeriana in the interspecific F1 hybrids without blocking DNA, and co-hybridization was hardly detected. The average mitotic chromosome length of O. meyeriana was found to be 1.69 times that of O. sativa. A comparison of 4,6-diamidino-2-phenylindole staining showed that the chromosomes of O. meyeriana were more extensively labelled, suggesting that the G genome is amplified with more repetitive sequences than the A genome. In interphase nuclei, 9-12 chromocenters were normally detected and nearly all the chromocenters constituted the G genome-specific DNA. More and larger chromocenters formed by chromatin compaction corresponding to the G genome were detected in the hybrid compared with its parents. During pachytene of the F1 hybrid, most chromosomes of A and G did not synapse each other except for 1-2 chromosomes paired at the end of their arms. At meiotic metaphase I, three types of chromosomal associations, i.e.O, sativa-O, sativa （A-A）, O. sativa-O, meyeriana （A-G） and O. meyeriana-O, meyeriana （G-G）, were observed in the F1 hybrid. The A-G chromosome pairing configurations included bivalents and trivalents. The results provided a foundation toward studying genome organization and evolution of O. meyeriana.     

大麦G—显带核型的研究

本文报道了 ASG 法处理的三个栽培大麦(Hordeum Vulgare)品种 G-带的核型研究。结果表明无论是早中期或中期染色体都显示出了密切邻近的、多重的 G-带带纹。在有丝分裂过程中染色体愈浓缩带纹数目愈少。同源染色体之间带纹分布的位置、染色深浅以及带纹数目都基本一致,可以较为准确地进行配对。同一分裂时期不同染色体的 G-带带纹各具一定的特点,可以作为鉴别的标记。讨论了显带技术和中期染色体的 G-带等问题。     

羊驼染色体核型及其G分带的研究

为了从选种、杂交改良、疾病诊断以及性别决定的遗传机制等方面为羊驼的繁育与推广提供更为有效的细胞遗传学资料,本试验采用外周血淋巴细胞培养法及胰酶-EDTA法分析了23只胡阿基亚型羊驼（Huacaya alpaca,雌20只,雄3只）的染色体核型及其G-分带,结果表明：羊驼二倍体染色体数目为2n=74,雄性羊驼核型为74,XY;雌性羊驼核型为74,XX。其中,1～20对常染色体为亚端着丝粒染色体,21～36对常染色体为亚中着丝粒染色体和中着丝粒染色体,X为中着丝粒染色体,Y为端着丝粒染色体。G-带分析表明,羊驼G带明暗相间,显现出不同的带纹,且羊驼每对染色体都有其独特的带纹特征,其带纹数目和精细程度随着染色体长度的增加而增加。Abstract: Blood samples from 23 Huacaya alpacas, 3 males and 20 females, were used to study chromosomes and karyotypes, so as to provide some effective cytogenetic bases for the selection, improvement by crossing, disease diagnosis of alpacas, and genetic mechanisms of sex determination. Peripheral blood lymphocyte culture was used to prepare chromosome. A method of trypase-EDTA was used for G-banding. The results showed as follows: The number of diploid chromosomes was 2n=74, with the karyotype 74, XY and 74, XX for males and females respectively. Thirty-six homologous pairs of chromosomes were autosomes, in which chromosomes pairs No.1 to No.20 were acrocentric-subterminal and No.21 to No.36 metacentric-submetacentric. And X chromosome was metacentric, Y chromosome telocentric. The analysis of G-bands showed that bright and dark bands appeared by turn. It showed different bands. And every pair of chromosomes had its distinct band, and the longer the chromosomes, the more the number of bands, and the more clear the bands.     

黄鳝二价染色体上地高辛配基标记随机引物原位DNA合成的研究

在黄鳝二价染色体上, 运用地高辛配基标记的随机引物原位DNA合成技术诱导出了明暗相间、基本稳定且类似于R带的带状结构。本文对该结果进行了较详细的分析和讨论。 Abstract:The dark bands alternating with light bands,relatively stable and R-band-like structure was showed on the pachytene bivalents of Rics-field eel(Monopterus albus Zuiew)by using the random-primed in situ digoxigenin-labelled DNA synthesis technique,and the results were analysed and discussed in detail.     

Chromosome G—banding in plants by inducing with trypsin and urea

Clear G-bands were revealed by applying the TUG method on chromosomes of 5 species of higher plants(Lilium davidii,Viciafaba,Hordeum vulgare,Ginkgo biloba and Triticum monococcum).Some details of the TUG method which consisted of treating chromosomes with both trypsin and urea were also studied.The mechanisms that might account for the presence of G-bands in plants were discussed.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

杆状病毒出芽病毒粒子膜融合蛋白的研究进展

杆状病毒是一类感染节肢动物的病原微生物,其基因组为双链环状DNA,大小为80～180kb.     

Inception of the Modern Public Health System in China and Perspectives for Effective Control of Emerging Infectious Diseases: In Commemoration of the 140th Anniversary of the Birth of the Plague Fighter Dr. Wu Lien-Teh

In this article, we systematically review Dr. Wu Lien-Teh's academic achievements and outstanding contributions in the prevention and control of the plague epidemic in northeast China and introduce the development of the earliest public health epidemic prevention system in China in order to commemorate the 140th anniversary of Dr. Wu Lien-Teh's birth. We hope that this article will provide insights into the effective prevention and control of emerging infectious diseases as well as the current worldwide pandemic of COVID-19, facilitating the improvement and development of public health systems in China and around the globe.