6个西洋梨品种染色体数目鉴定

用去壁低渗-火焰干燥-Gemsa染色法观察了极早熟品种保利阿斯卡、朱丽比恩，早熟品种利布林、特雷沃、玉璧林达及中熟品种芦卡斯6个西洋梨品种的染色体数目。结果表明．玉璧林达、芦卡斯为三倍体（2n=3x=51），其余4个品种为二倍体（2n=2x=34），多倍体出现率为33．3％。同时，经过初步测定，玉璧林达的花、果、叶均大，枝、干粗壮，均表现出一定的巨大性。利布林、特雷沃、朱丽比恩、保利阿斯卡为品质优良的早熟、极早熟品种，是天津地区很有发展前景的品种。搞清这6个西洋梨品种的染色体倍性，可为今后梨的遗传育种和梨树栽培提供依据。     

家猪(Sus scrofa domestica L.)染色体G-带核型的研究

本文对经外周血淋巴细胞培养的猪染色体标本,运用胰酶 G-带技术,进行了核型分析,描述了早、中、晚不同时期中期染色体的 G-带型。将家猪中期染色体 G-带型划分成64个区。共488条带纹,比较了染色体 X 和9的带型差别。     

牛未成熟卵母细胞体外受精及染色体分析

收集不同供体牛的卵母细胞并分成两组。体外成熟培养16h为不完全成熟组；体外成熟培养24h为完全成熟组。结果显示，体外受精48h后，成熟组大部分胚胎发育到8细胞期和16细胞期，不完全成熟组的多数胚胎发育到2细胞期和4细胞期。染色体异常发生率显著高于成熟组。染色体异常表现为单倍体、多倍体和混合倍体。引起染色体异常发生的原因可能是由于精子穿入时透明带或卵母细胞膜的功能障碍所引起。     

含E.coli F因子的马立克氏病病毒1型（MDV1）转移载体的构建及初步应用

【目的】为了构建MDV1细菌人工染色体，以便快速有效地进行重组病毒的筛选，进行了含E.coli F因子的马立克氏病病毒1型（MDV1）转移载体的构建。【方法】利用DNA重组技术，构建了含有E.coli F因子的马立克氏病病毒1型（MDV1）转移载体，利用脂质体，将线性化的转移载体转染入已感染CVI988病毒的CEF，用MX-HAT药物筛选3代以后，用X-gal染色,挑取阳性克隆。【结果】经测序分析发现，人工体外合成的单一loxP位点，序列正确，另外，同源重组左臂和右臂序列正确，并且相对连接。利用SphⅠ和NheⅠ双酶切，鉴定出含有同向LoxP位点的转移载体，将其命名为pUS-BGS。将该载体用NheⅠ线性化后，用脂质体转染已感染CVI988病毒的CEF，用MX-HAT药物筛选3代以后，X-gal染色，可以观察到呈现蓝色的重组病毒。【结论】本研究报道了含有E.coli F因子以及两同向的loxP位点的MDV1转移载体的构建，利用该载体可以有效地进行重组病毒的筛选，为下一步MDV1细菌人工染色体的构建奠定了基础。     

Construction of chromosomal segment substitution lines and genetic dissection of introgressed segments associated with yield determination in the parents of a super‐hybrid rice

Heterosis is a phenomenon whereby hybrids of inbred lines produce favourable phenotypes that exceed those of their parents. Traits of interest are higher yield and stronger stress tolerance. The two‐line super‐hybrid rice ‘Liangyoupei9’ (LYP9) shows superiority to both its elite inbred line ‘93‐11’ and ‘Pei'ai64s’ (‘PA64s’) parents and conventional hybrids. However, the genetic basis of its hybrid vigour, especially yield determination, remains elusive. In the present study, a set of 156 chromosome segment substitution lines (CSSLs) carrying overlapping segments from ‘PA64s’ in a genetic background of ‘93‐11’ were constructed and planted in six environments. Three major agronomic traits, viz. panicle length (PL), heading date (HD) and plant height (PH), and five yield‐related traits, viz. grain weight per panicle (GWP), number of grains per panicle (GPP), 1000‐grain weight (TGW), seed set (SS) and number of panicles of per plant (PPP), were evaluated over 3 years. Quantitative trait loci (QTL) analysis was conducted using a likelihood ratio test based on stepwise regression. Forty‐six putative QTL distributed on 11 chromosomes were detected in more than one year. Remarkably, GWP of four CSSLs carrying positive yield QTL outperformed the recurrent parent ‘93‐11’ by more than 15%, in at least two environments. These results indicate that CSSLs are effective in identifying yield‐associated traits, and lines harbouring such QTL will be rich in resources for future molecular breeding programmes.     

Homoeological relationships between the f chromosome of Brassica rapa and the e chromosome of Brassica oleracea

Eight plants of the putative double monosomic addition line (DMAL, 2n= 20) were developed by crossing a monosomic chromosome addition line of radish [f(A)‐type monosomic addition line (MAL) (2n= 19)] carrying the f chromosome of Brassica rapa (2n= 20, AA) with another [e(C)‐type MAL (2n= 19)] having the echromosome of Brassica oleracea (2n= 18, CC). The homoeological relationships between the two alien chromosomes were investigated by morphological, cytogenetic and random amplified polymorphic DNA (RAPD) analysis. Seventeen morphological traits that were not present in the radish cv. ‘Shogoin’ were observed in both MALs and these traits were substantially exhibited in DMAL plants. At the first metaphase of pollen mother cells (PMCs), the two parental MALs showed a chromosome configuration of 9II +1I, demonstrating impossibility of recombination between the R and the added chromosomes. The DMALs formed 10II in approximately 73% of PMCs, with one bivalent showing loose pairing between two chromosomes differing in size. In an attempt to identify the two MALs by RAPD‐specific markers using 26 selected random primers, 13 and 20 bands were specific for the f(A)‐type and the e(C)‐type MALs, respectively; 12 bands were common to both MALs (26.7%). In conclusion, the f chromosome of B. rapa is homoeologous to the e chromosome of B. oleracea. The genetic domain (genes) for 17 morphological traits are linked to each homoeologous chromosome bearing 27% of the corresponding RAPD markers.     

植物染色体原位杂交技术的发展

染色体原位杂交技术是现代生物技术的重要组成部分。它具有直接、准确、便捷等特点,在生物科学研究中发挥着重要的作用。随着分子生物学的进步,染色体原位杂交技术不断改进和完善,新的染色体原位杂交技术不断涌现。本文对染色体原位杂交探针、染色体原位杂交靶DNA类型、染色体原位杂交新技术及应用等方面进行了综述。     

RNA干扰MSTN基因鲤的肌纤维密度及染色体核型分析

本实验分析RNA干扰MSTN基因鲤(以下简称RNA干扰鲤,体质量为116.2g和110.3g)的染色体,测定该鲤肌肉中的肌纤维密度。结果表明:(1)三组实验鱼的肌纤维密度分别为163.7根/mm~2、171.9根/mm~2和162根/mm~2,对照鱼的普通鲤(Common carp)为142根/mm~2,实验鱼高于对照鱼。单因素方差分析表明:实验鱼组间肌纤维密度差异不显著(F=0.83,P=0.440.05),而与对照鱼差异显著(F=5.24,P=0.0340.05)。(2)PHA和秋水仙素体内注射法分析核型表明,实验鱼的染色体数为2n=100,核型公式为:2n=30m+24sm+28st+18t,臂比(NF)156,对照鱼染色体数为2n=100,核型公式为:2n=30m+26sm+28st+16t,臂比(NF)156。结果说明RNA干扰基因的插入并未影响鲤染色体组成。     

不同预处理方法对柠檬桉染色体制片技术的影响

以柠檬桉种子的根尖为研究材料,通过比较了3种浓度的秋水仙素、2 mmol·L-1的8-羟基喹啉、冰水混合物及以不同比例冰水混合物和0.1%的秋水仙素的混合液等预处理,在多个时间梯度对柠檬桉根尖染色体制片的影响进行了研究,结果发现：3种浓度秋水仙素预处理中,0.1%秋水仙素预处理1.5 h的染色体浓缩适中,分散性好,有较多的分裂相;2 mmol·L-1的8-羟基喹啉预处理的染色体均分散性较差,且分裂相较少;冰水混合物预处理12 h 的染色体浓缩适中且分裂相较多,分散程度较好。其余处理时间的染色体浓缩程度不理想,不易进行染色体分析;混合液中2：3比例下的染色体分散性较好,且浓缩程度适中,有较多的分裂相,综合比较结果由优到劣的处理方法为：0.1%秋水仙素预处理1.5 h＞2：3混合液＞冰水混合物处理12 h＞2 mmol·L-1的8-羟基喹啉,其中在上午11：30—12：30取材,0.1%的秋水仙素处理根尖1.5 h,效果最佳。     

卫星搭载对羊草种子萌发及细胞学效应的研究

试验研究了"实践八号"航天育种卫星搭载羊草种子后的萌发及根尖细胞学效应。结果表明:太空诱变后羊草种子的萌发能力降低,但与对照差异不显著(P>0.05);太空诱变促进了羊草根尖细胞的有丝分裂活动,分裂指数较对照增加24.17%;太空诱变使羊草根尖细胞在有丝分裂过程中产生微核、染色体断片、染色体粘连、落后染色体、游离染色体等畸变类型。其中,单微核是主要的核畸变类型,染色体断片为主要的染色体畸变类型。"实践八号"卫星搭载对羊草根尖细胞有明显的诱变效应。