外生菌奶真菌鳞柄白毒鹅膏减数分裂和担孢子形成的 …

利用双苯并咪唑染色法对鳞柄白毒鹅膏减数分裂和孢子形成的各个时间进行观察,并且通过对减裂各期的反复观察,认为鳞柄白毒鹅膏的染色体数目减数分裂形成四个核,对应形成个单核担孢子,然后核在担孢子中进行一次有丝分裂,形成四个双核提孢子。     

红芪染色体数目及核型分析

红芪为多年生草本植物。以道地红芪为材料,采用常规压片法制片,结合显微摄影技术,研究了红芪染色体数及其核型,旨在为红芪种质鉴定、起源分析、物种演替、良种培育提供必要的细胞学依据。结果表明,红芪的染色体为二倍体,染色体数目为14,染色体核型公式是2n=14=10m+4sm;其中第4号和第7号染色体为近中着丝粒染色体,其余染色体均为中间着丝粒染色体;核型不对称系数为60.45%,属于"2A"型,是一种原始类型。     

植物染色体C-带带型制作技术的改良

利用黄瓜新泰密刺种子根尖为材料,制作黄瓜中期染色体C显带制片,得到清晰稳定的染色体C显带带纹,在采用常规压片和去壁低渗的制片方法的基础上,对植物染色体显带的制片方法进行了改进。结果显示,利用改良后的方法得到了较多的且清晰稳定的黄瓜中期染色体C显带带纹,其单倍染色体带纹总数为30。结论:染色体制片中的解离、压片、干燥等多个步骤对染色体显带有显著的影响。     

小麦染色体标本制备方法的优化

制备出分裂相多、杂质少、背景清晰、染色体分散且形态好的染色体标本,一直是细胞遗传学实验课关注的重点和难点.本文在去壁低渗火焰干燥法的基础上,改良了小麦染色体制片方法,分析了影响染色体标本制备效果的主要因素.     

Development of <Emphasis Type="Italic">Gossypium barbadense</Emphasis> chromosome segment substitution lines in the genetic standard line TM-1 of <Emphasis Type="Italic">Gossypium hirsutum</Emphasis>

Chromosome segment substitution lines （CSSL） consist of a battery of near-isogenic lines that have been developed and cover the entire genome of some crops. With the exception of one homozygous chromosome segment transferred from a donor parent, the remaining genome of each CSSL line is the same as the recipient parent. It is an ideal material for genome research and particularly QTL mapping. In the present study, we first developed one set of CSSL lines using G hirsutum acc. TM-1 （the genetic standard）, as the recipient parent and G barbadense cv. Hai7124 as the donor parent using molecular assistedlselection in BC5S1-3 generations. The CSSL consisted of 330 different lines, in which 1-4 different lines had the same or overlapping substituted segments. The genetic length of the substituted segments covered 5271.9 cM with an average segment distance of 10.9 cM, 1.5 times the total genetic length of Upland cotton （3514.6 cM）. The substituted segments of each line varied in length, ranging from 3.5 cM for the shortest segment to 23.2 cM in the longest segment. Our CSSL have not yet to cover the entire tetraploid cotton genome, due to the absence of some donor parent interval segments.     

Analysis of DNA methylation variation in wheat genetic background after alien chromatin introduction based on methylation-sensitive amplification polymorphism

During the process of alien germplasm introduced into wheat genome by chromosome engineering, extensive genetic variations of genome structure and gene expression in recipient could be induced. In this study, we performed GISH （genome in situ hybridization） and AFLP （amplified fragment length polymorphism） on wheat-rye chromosome translocation lines and their parents to detect the identity in genomic structure of different translocation lines. The results showed that the genome primary structure variations were not obviously detected in different translocation lines except the same 1RS chromosome translocation. Methylation sensitive amplification polymorphism （MSAP） analyses on genomic DNA showed that the ratios of fully-methylated sites were significantly increased in translocation lines （CN12, 20.15%; CN17, 20.91%; CN18, 22.42%）, but the ratios of hemimethylated sites were significantly lowered （CN12, 21.41%; CN17, 23.43%; CN18, 22.42%）, whereas 16.37% were fully-methylated and 25.44% were hemimethylated in case of their wheat parent. Twenty-nine classes of methylation patterns were identified in a comparative assay of cytosine methylation patterns between wheat-rye translocation lines and their wheat parent, including 13 hypermethylation patterns （33.74%）, 9 demethylation patterns （22.76%） and 7 uncertain patterns （4.07%）. In further sequence analysis, the alterations of methylation pattern affected both repetitive DNA sequences, such as retrotransposons and tandem repetitive sequences, and low-copy DNA.     

小麦易位系基因组DNA甲基化分析中MSAP体系建立及应用

DNA甲基化在真核生物生长发育过程中起着重要调控作用.依据对DNA甲基化敏感程度不同的同裂酶,在AFLP(amplified fragment length polymorphism)基础上发展而来的MSAP(methylationsensitive amplification polymorphism)技术可以方便的检测全基因组DNA胞嘧啶甲基化模式及程度.本文以一套高代分离的小麦黑麦1RS/1BL易位系及其亲本材料为研究对象,采用EcoRⅠ和HpaⅡ(或MspⅠ)双酶切建立适合于小麦易位系基因组的MSAP技术体系,针对研究中出现的问题提出解决方法,并对酶切位点的甲基化模式进行分析,检测易位系及亲本材料间的甲基化多态性,为进一步的基础研究和育种应用提供理论依据.