毛白杨花粉母细胞减数分裂及其进程的研究

采用细胞遗传学方法对毛白杨 (PopulustomentosaCarr.)花粉母细胞减数分裂及其进程进行了研究 .结果表明 :①毛白杨花粉母细胞减数分裂进程有一定的规律 ,且与花序的形态和花药颜色变化有密切相关 ;②减数分裂染色体行为表现因个体不同而不同 ,终变期、中期Ⅰ有数目不等的单价体出现 ,在后期Ⅰ乃至末期Ⅰ、末期Ⅱ可见到单独存在的落后染色体 ,体现了毛白杨遗传上的异质性 ;③毛白杨减数分裂存在多核仁现象 ,在末期Ⅰ、末期Ⅱ最多可见到含 8个小核仁的子核 ,并且随着减数分裂进行 ,多个小核仁发生合并 ,最终生成一个大核仁 ;④毛白杨各无性系在减数分裂进程上存在着差异 ,甚至同一雄性无性系植株的不同花芽或同一花芽上不同部位等 ,其花粉母细胞减数分裂时期也表现为不同步性 ,显示了种群变异的多样性和丰富性     

Chromosome locations of leaf rust resistance genes in selected tetraploid wheats through substitution lines

Langdon durum D-genome disomic substitution lines were used to study the chromosome locations of adult-plant leaf rust resistance genes identified from tetraploid wheat accessions. The accessions are 104 (Triticum turgidum subsp. dicoccum var. arras) and 127 (T. turgidum subsp. durum var. aestivum). The complete sets of the substitution lines were crossed as female parents with the accessions and F₁ double monosomic individuals selected at metaphase I. Segregating F₂ individuals were inoculated during the flag leaf stage with pathotype UVPrt2 of Puccinia triticina. The substitution analysis involving accession 104 showed that the gene for leaf rust resistance is located on chromosome 6B. The analysis with accession 127 indicated that chromosome 4A carries a gene for leaf rust resistance. The two novel genes are temporarily designated as Lrac104 and Lrac127, respectively from accessions 104 and 127.     

The Genomic Relationships Among Glycine soja Sieb. and Zucc., G. max (L.) Merr. and 'G. gracilis' Skvortz.

The objective of this study was to establish genomic relationships among G. sojii, G. max, and ‘G. gracilis’ based on cytogenetic analyses. All three species hybridized readily, though pod set was low (2.2 %—5.3 %); seeds produced viable, vigorous and totally fertile F, plants which were normal in meiotic pairing. This suggests that all three species-belong to one gene pool and should be considered as forms of one species.     

毛白杨起源的细胞遗传学研究

对毛白杨(PopulustomentosaCarr.)花粉母细胞减数分裂观察发现,其同源染色体联会较差,在终变期、中期Ⅰ可见到出现频率较高的单价体,在后期Ⅰ、末期Ⅰ亦可经常见到落后染色体的存在,证明部分同源染色体间存在一定程度的异质性,即毛白杨属杂种起源.进一步依据毛白杨、新疆杨和它们的杂种毛新杨染色体的联会情况及花粉育性等推断,银白杨或新疆杨有可能作为起源亲本之一参与了毛白杨种的形成.     

Analysis of Disequilibrium Hybridization in Hybrid and Backcross Progenies of Saccharum officinarum × Erianthus arundinaceus

Erianthus arundinaceus is an important, closely related genus of Saccharum officinarum L. It is therefore important to understand how the chromosomes are transmitted when it hybridizes with sugarcane. The hybrids and backcross progenies of S. officinarum and E. arundinaceus and their parents were used for Karyotype analysis and to study the law of chromosome transmission. The results showed that the somatic chromosome number of both of the E. arundinaceus Hainan92-105 and Hainan92-77 were 2n = 60 = 60sm, belonging to type 1 A, and the BC1 YC01-21 was 2n = 104 = 100m ＋ 4sm, belonging to type 2C. The other six tested clones belonged to type 2B. The both F1s YC96-66 and YC96-40 that originated from Badila （2n = 80 = 70m ＋ 10sm） with E. Arundinaceus were 2n = 70 = 68m ＋ 2sm, which suggests an n ＋ n transmission. The cross between YC96-66 （female parent） and CP84-1198 （male parent, 2n = 120 = 114m ＋ 6sm） also followed the same genetic law and the somatic chromosome number of their progeny, YC01-3 （2n = 105 = 95m ＋ 10sm）. The cross derived from YC96- 40 （female） and CP84-1198 （male）, YC01-21 had 2n = 104 = 100m ＋ 4sm chromosomes, following the same genetic law of n ＋ n. However, YC01-36 had 2n = 132 = 130m ＋ 2sm chromosomes, which suggests a 2n ＋ n chromosome transmission. It can be inferred that the inheritance of chromosomes was very complex in the BC1. The difference in chromosome number between clones was as high as 28. This could be explained by the 2n ＋ n transmission of chromosomes. In addition, as there was not be a regular number of haploids, this phenomenon is termed as disequilibrium hybridization.     

Karyotypes and chromosome association in aneuploid varieties of Japanese garden iris,Iris ensata Thunb

Summary Karyotypes, chromosome association and pollen fertility of aneuploid varieties (2n=25), Ochibagoromo, Matsusakatsukasa and Isehomare in Iris ensata were analysed and compared with those of eu-diploid varieties (2n=24), Shishinden, Kachô and Asahimaru. The somatic chromosome complement of the aneuploid varieties consisted of 11 pairs and 3 singles of chromosomes and that of the eu-diploid varieties 12 pairs of chromosomes. The singles of chromosomes in the aneuploid varieties had similarity with one another and with a pair of chromosomes in the eu-diploid varieties. The high frequency of normal association was present in the eu-diploid varieties, and this indicated that 12 pairs of chromosomes had full homology between each other. In contrast, the mean chromosome association per cell in an aneuploid variety Ochibagoromo was 4.615_I+10.067_II+0.077_III+0.005_IV, indicating that the chromosome complement of this variety consisted of 11 pairs and 3 singles and that these singles had partial homology among them. The eu-diploid varieties exhibited high pollen fertility due to their regularity of chromosome association; the aneuploid varieties considerably lower fertility, i.e. 28.2% for Ochibagoromo, 31.8% for Isehomare and 43.8% for Matsusakatsukasa. The primary cause for the low fertility of these varieties seemes to be the partial homology among 3 single chromosomes. Finally, the origin and the development of the aneuploid varieties were discussed.     

Cytogenetic analysis of translocations in cotton

In order to create cotton translocation lines, 191 translocations were recovered as heterozygotes following combined treatment of seeds by colchicine and γ‐rays, irradiation of seeds by thermal neutrons and c‐irradiation of pollen. Cytogenetic analysis showed that chromosome translocations involving two chromosomes arose more often (180) than those involving three chromosomes (11). The heterozygous translocations were characterized by different formation and frequencies of the multivalents at metaphase I of meiosis. Only 104 translocations were characterized by a multivalent frequency of more than 0.25 per cell. Most of the translocations (156) exhibited a high meiotic index, but 11 were characterized by a decreasing meiotic index and by an increase in the percentage of tetrads with micronuclei. The pollen fertility of translocations differed significantly and varied from high fertility to pollen sterility. The high frequency of abortive pollen grains was typical for about one half of translocations studied. The translocations were made homozygous and as a result, 12 new reciprocal homozygous translocation lines were obtained in cotton.     

一例真间性猪的研究

【目的】为探讨间性猪的生殖遗传发育基础和优化猪的种质资源,对一例间性猪进行了外部形态、细胞遗传、性激素、解剖以及组织病理学的研究。【方法】5月龄间性大白猪为试验组,以与试验组同窝的正常公母猪为对照组,分别进行内外生殖器官检察;PCR检测SRY基因;染色体组型和带型分析,取外周血进行常规短期淋巴细胞培养,获取中期细胞分裂相,制成染色体标本,G显带和C显带处理;放射免疫法测定静脉血睾酮(testosterone, T)、雌二醇(estradiol, E2)、促黄体素(luteinizing hormone, LH)、促卵泡素(follicle- stimulating hormone, FSH)、孕酮(progesterone, PRG)和催乳素(prolactin, PRL)含量;生殖腺病理切片制做及观察,取2 cm×2 cm大小生殖腺组织,10%甲醛固定后进行常规石蜡切片制作,苏木(Hematoxylin)与伊红(Eosin)染色(H.E.染色),镜检并显微照相;下丘脑和垂体电镜切片制做及观察,取2 mm×2 mm大小脑部组织,2.5%戊二醛固定后进行常规电镜切片制作,透射电镜观察并拍摄。【结果】结果表明,间性猪外生殖器为雌性表型,外阴位于肛门下方,阴蒂肿大突出于阴门之外,左侧可见睾丸,右侧隐睾,阴囊发育良好。间性猪和正常母猪染色体组型为38, XX,SRY阴性,核型组成为10sm+4st+12m+12t,G带带型没有差异,C带的显带基本相似,1、3、4、6、8、9、10、13、14和16号染色体均不同程度显带,以圆形带为主。试验组和对照组各号染色体的相对长度及臂比值差异均不显著（P＞0.05）。睾酮和雌二醇水平均介于正常公、母猪之间,促黄体素、促卵泡素、孕酮和催乳素水平均高于正常母猪,LH/FSH比值明显低于正常母猪。剖检发现间性猪有雌雄两性生殖腺,有两个卵睾体,左侧有附睾,子宫体、子宫角和阴道明显退化,阴蒂中隐藏有假阴茎。病理组织镜检发现卵睾体为睾丸和卵巢混合组织,柱状上皮细胞退化,有正常莱氏细胞,无精原细胞或其残留物存在;附睾假复层纤毛柱状上皮细胞正常,内腔无精细胞或其残留物;子宫内膜有较低程度退化,部分内膜腺正常。试验组下丘脑和垂体分泌细胞较对照组发达,促性腺激素释放激素（gonadotropin-releasing hormone, GnRH）神经元核大且饱满,细胞器增多并融合;垂体以促性腺激素细胞为主,细胞数量明显增多,分泌颗粒大小不均;催乳素细胞数量较正常母猪多,分泌颗粒电子密度也较大。【结论】该间性猪为真间性,无染色体易位现象,性激素紊乱,无种用价值。     

Riverine status and genetic structure of Chilika buffalo of eastern India as inferred from cytogenetic and molecular marker-based analysis

The present study aimed at assessing the status of the Chilika buffalo population of eastern India employing cytogenetic and molecular markers. The Chilika buffaloes investigated cytogenetically possess a somatic chromosome count of 50, identical to that of typical riverine buffaloes. Various diversity estimates, viz. observed number of alleles (4.68), effective number of alleles (2.79), and observed (0.487) and expected (0.602) heterozygosity across 25 heterologous microsatellite markers indicated the presence of a moderate level of genetic diversity in Chilika buffaloes, comparable with three other prominent Indian riverine buffalo breeds (Murrah, Nagpuri and Toda) included in this study. Across the four buffalo populations, mean estimates of F -statistics from Jackknifing over loci were significantly different from zero (p < 0.05), with F _IT (total inbreeding estimate) = 0.315 ± 0.038, F _IS (within-population inbreeding estimate) = 0.178 ± 0.038, and F _ST (population differentiation) = 0.166 ± 0.025. Inter-breed analysis reflected Chilika buffaloes to be genetically close to Nagpuri followed by Murrah and Toda buffaloes. Factorial correspondence analysis (FCA) revealed low breed-specific clustering of Chilika and Nagpuri buffaloes. Additionally, the neighbour-joining tree structure of mitochondrial DNA D-loop haplotypes indicated clear grouping of the Chilika haplotypes with the riverine buffalo. Thus the cytogenetic, microsatellite and mitochondrial data analysed in the present study classify Chilika buffalo of eastern India to be of the riverine type and not swamp-type buffalo.