白木香染色体制片方法的研究

为获得清晰的染色体图像,应用改良去壁低渗法对白木香茎尖的染色体标本制备进行了探讨,并比较了2种不同预处理方法制片的效果以及不同的预处理时间对细胞中期分裂相的影响．结果表明,选取早上9点钟左右的茎尖,用w=0．1％的秋水仙素溶液预处理2h后固定24h,再用w=2％的纤维素酶和埘：0．5％的果胶酶混合酶液于37℃下进行2h的酶解,低渗后制备染色体标本,能获得分散良好、清晰的染色体图像．首次确定了白木香的染色体数目（2n）为16条．     

厦门港中华哲水蚤染色体组型

以采自厦门港中华哲水蚤为材料,采用秋水仙素溶液浸泡、热滴片、空气干燥、Ｇｉｅｍｓａ染色等方法,进行染色体标本制备,并对厦门港中华哲水蚤中期染色体形态了作了分析研究,结果表明,中华哲水蚤染色体数目为ｎ＝１１,２ｎ＝２２,其核型公式为２ｎ＝１２ｍ＋６ｓｍ＋２ｓｔ＋２ｔ,对厦门港不同世代的中华哲水蚤染色体进行比较,分析并讨论。     

染色体条纹提取算法研究及应用

提出一种基于灰度阈值的染色体条纹提取方法.利用染色体内部的灰度差异,采用改进的Bernsen算法求取局部阈值;通过迭代二分算法进行染色体区域标定,划分图像的灰度等级,锐化图像;利用锐化图像的灰度直方图提取有效灰度段,获得准确的染色体条纹.最后,应用本文的算法对200张染色体样本图进行测试,试验证明本文算法所提取的条纹清晰准确、噪声干扰小,对染色体的分离算法研究有一定的指导意义.     

Primary investigation on GISH-NOR in cotton

Six loci of nucleolar organizer region (NOR) were detected in genomic in situ hybridization (GISH) of cotton (Gossypium). NOR was the characteristic of 45S rDNA but could be generated by genomic DNA (gDNA) extracted from Gossypium species as probe. With twice FISH to the same mitotic cell of G herbaceum or G hirsutum, number, position and size for NORs generated from 45S rDNA and gDNA were identified largely similar or even the same. The NORs with gDNA as probe were therefore permanently defined as GISH-NORs. GISH-NORs from G hirsutum and Graimondii mitotic images were all terminal types. Four and two GISH-NORs from G herbaceum (var. africanum) were terminal and centromere types, respectively. Six GISH-NORs in G hirsutum were chromosome mapped with two in A- and four in D-subgenomes. There were also GISH-NORs in mitotic image of G raimondii with its own gDNA as probe. From mitotic image of G herbaceum with its own gDNA as probe, GISH-NOR could not be observed but non-wholerecovery of hybridized signals was distinguished. These non-whole-recovery of hybridized signals were detected on long arm terminals of most chromosomes and especially existed in nearly half long arm of a pair of chromosomes in Gherbaceum gDNA probed itself GISH image, which may be possibly induced by low copy genes within the regions rather than inter-subgenomic segment translocations. GISH-NORs in G hirsutum mitotic images were dominantly observed when gDNAs from D and A genome species were used as probes and block, respectively, but not when the reverse probe and block gDNA from the two diploid progenitor genomes were designed. There may be two speculations to this special phenomenon: rDNA concerted evolution; content of rDNA in genome D more than genome A.     

甲基杀虫脒盐酸盐在小鼠体内致突变研究

甲基杀虫脒盐酸盐作为一种化学诱变物具有一定致突变性。本研究设计中突变的最低剂量组1/50LD50=4.48mg/kg体重,在小鼠骨髓细胞微核出现率中,与对照组比较,呈极显著性差异。因此,无作用剂量组应低于4.5mg/kg体重。染色体畸变的最低剂量在1/5LD50与阴性对照组有极显著性差异,染色体畸变的无作用剂量在8.95～44.76mg/kg范围内。     

陆地棉遗传标准系TM-1背景的海岛棉染色体片段置换系的培育

染色体片段置换系(chromosome segment substitution lines, CSSL)基因组内只含有一个来自供体亲本的染色体片段, 而基因组的其余部分与轮回亲本相同, 并能把QTL拆分为单个的孟德尔因子, 因此CSSL是进行基因组分析, 特别是QTL分析的理想材料. 本研究以陆地棉遗传标准系TM-1为受体亲本, 海岛棉海7124为供体亲本在BC₅S₁代借助分子标记辅助选择(marker-assisted selection, MAS)培育了一套染色体片段置换系. 这套置换系由330个株系构成; 1~4个不同的株系携带相同的染色体片段, 置换片段的平均长度为10.9 cM, 总长度为5271.9 cM, 是棉花基因组总长度3514.6 cM的1.5倍. 每个株系内被替换的染色体片段长度不一, 最短为3.5 cM, 最长为23.2 cM. 由于还有些区段缺失供体亲本的染色体片段, 所以这个替换系群体没有完全覆盖棉花基因组.     

氯霉素对蚕豆根尖细胞有丝分裂的影响

氯霉素在动物性食品中的残留对人类健康造成威胁。用不同浓度氯霉素处理蚕豆根尖，结果表明，氯霉素会造成蚕豆根尖细胞有丝分裂指数下降，微核率上升和染色体畸变，畸变类型主要有染色体落后、染色体断片、染色体桥和染色体多极分裂等。染色体异常行为与氯霉素处理浓度呈正相关，说明氯霉素是一种环境诱变剂。     

DYS19、DYS391、DYS439基因座多态性及其荧光标记复合扩增检测的研究

目的：研究Y-染色体STR基因座多态性,建立Y-STR复合扩增及毛细管电泳检测单倍型的方法。方法：应用荧光标记引物,建立DYS19,DYS391,DYS439三个Y-STR基因座复合PCR扩增体系,并应用毛细管电泳技术检测110名武汉汉族男性无关个体的DYS19,DYS391,DYS439 Y-STR基因座分型。结果：DYS19,DYS391,DYS439三个Y-STR基因座分别被检出6,5,3个等位基因,GD值分别为0．7385,0．4780,0．5747。110名无关个体中发现32种单倍型,其单倍型GD为0．9351。结论：Y-STR多态性及其荧光标记、复合扩增及毛细管电泳的检测方法在法医学应用中具有重要作用。     

贵州疣螈的核型研究

以脾脏细胞制作染色体标本，研究了贵州疣螈的核型，结果表明：体细胞染色体数为２ｎ＝１２４，第６、７对是亚中部着丝粒染色体，第１２对是亚端部着丝粒染色体，其余９对均为中部着丝粒染色体。未发现异形染色体对，本文还对已知近缘种进行了核型比较。     

蓝曼龙(Trichogaster trichopterus)的染色体组型、Ag-NORs及C-带型的研究

以肾细胞作材料，采用秋水仙素-低渗-空气干燥法、Howell[1980]的方法(银染)和Sumher(1972)的方法(C带)，制作染色体标本．首次报道了蓝曼龙(Trichogaster trichopterus)的核型及银染和C带。结果显示出：蓝曼龙的核型公式为2n=46t，NF=46，具有1对银染分别位于t1的一对同源染色体上的臂的端部，其染色体上NORs有明显的大小差异，结构和数目在不同的细胞中也出现了多态性,其深染C-带区可以分为着丝粒C-带，端粒C-带，居间C-带，没有发现异型性染色体。