遗传多代的13/21罗伯逊易位家系的调查研究

一个13/21染色体罗伯逊易位家系中, 易位染色体携带者4人,易位型先天愚 型患者3人,易位染色体至少已经遗传了4代。该家系中有同性双生子的聚集现象。讨论 了罗伯逊易位的遗传机理。 Abstract:A pedigree with 13/21 robertsonian translocation was reported.There were four carriers and three patients with Downs syndrome in the padigree.The Robertsonian chromosome translocation had been transmitted at leart for four generations.A family aggregation of monozygotic twines was found in this pedigree too.The inheritance principle of robertsonian translocation was discussed and that the origin of monozygotic twins may be genetically involved were considered.     

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.     

Characterization of Interspecific Hybrids Between Oryza sativa L. and Three Wild Rice Species of China by Genomic In Situ Hybridization

In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice （Oryza sativa L.）. In the present study, hybrids between O. sativa （AA genome） and three Chinese wild rices, namely O. rufipogon （AA genome）, O. officinalis （CC genome）, and O. meyeriana （GG genome）, were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization （GISH） was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4＇,6＇-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.     

Inducement of chromosome translocation with small alien segments by irradiating mature female gametes of the whole arm translocation line

Haynaldia villosa Schur. (syn. Dasypyrum villosum Candargy, 2n=14, VV) has been proved to be an important genetic resource for wheat improvement. The development of translocation with small alien chromosome segments, especially interstitial translocation, will be helpful for better utilization of its useful genes. Up to now, most of the reported Triticum aestivum – H. villosa translocation lines are involved in a whole arm or large alien fragments. In this paper, we report a highly efficient approach for the creation of small chromosome segment translocation lines. Before flowering, the female gametes of wheat-H. villosa 6VS/6AL translocation line were irradiated by 60CO-γ ray at 160 Rad/M dosage rate and three dosages (1600, 1920, 2240 Rad). Anthers were removed from the irradiated florets on the same day and the florets were pollinated with normal fresh pollens of T. aestivum cv. Chinese Spring after 2-3 days. Genomic in situ hybridization (GISH) at mitosis metaphase of root-tip cell of M1 plants was used to detect the chromosome structural changes involving 6VS of H. villosa. Among the 534 M1 plants screened, 97 plants contained small segment chromosome structural changes of 6VS, including 80 interstitial translocation chromosomes, 57 terminal translocation chromosomes and 55 deletion chromosomes. For the 2240 Rad dosage treatment, the inducement frequencies of interstitial translo-cation, terminal translocation and deletion were 21.02%, 14.01%, and 14.65%, respectively, which were much higher than those previously reported. The M2 seeds were obtained by backcrossing of 74 M1 plants involving 146 chromosomes structural changes of 6VS, and it was found that the structural aberrations in the M1 plants could be transmitted to their progenies. Irradiating mature female gametes of whole arm translocation is a new and highly efficient approach for creation of small segment chromosome struc-tural changes, especially for interstitial translocations.     

麻雀核型研究的新发现

本文对分布于牡丹江地区的麻雀（Passer montanus montanus Linnaeus）（指名亚种）进行了核型、C带和G带研究,发现了麻雀同一亚种内具有4种核型,即2n=78（正常）、2n=77、2n=76和2n=78（异常）。经分析比较认为,4种核型中,2n=78（正常）为基础核型,而其他3种核型是在此基础上由微小染色体发生过罗伯逊易位（Robertsonian translocation）形成的。从而为罗伯逊易位在鸟类核型进化中起重要作用这一推测提供了直接的证据。Abstract: The karyotype .C-band and G-band of the tree sparrow (Passer montanus montanus L.) in Mudanjiang area were studied, and 4 karyotypes were discovered, they are 2n=78 (normal), 2n=77,2n=76 and 2n=78(unusual). By analysis and comparison it can be considered that the 2n=78(normal) is a basic karyotype in the 4 karyotypes, and the others are formed by Robertsonina translocation between microchromosomes on this base, thus providing the inference that the Robertsonian translocation plays an important role in karyotype evolution of birds with direct evidence.     

Induction and transmission of wheat-Haynaldia villosa chromosomal translocations

In order to develop more wheat-Haynaldia villosa translocations involving different chromosomes and chromosome segments of H. villosa, T. durum-H, villosa amphiploid was irradiated with ^60Co γ-rays at doses of 800, 1,200, and 1,600 rad. Pollen collected from the spikes 1, 2, and 3 days after irradiation were transferred to emasculated spikes of the common wheat cv. ‘Chinese Spring＇. Genomic in situ hybridization was used to identify wheat-H, villosa chromosome translocations in the M1 generation. Transmission of the identified translocation chromosomes was analyzed in the BC1, BC2, and BC3 generations. The results indicated that all three irradiation doses were highly efficient for inducing wheat-alien translocations without affecting the viability of the M1 seeds. Within the range of 800-1,600 rad, both the efficiency of translocation induction and the frequency of interstitial chromosome breakage-fusion increased as the irradiation dosage increased. A higher translocation induction frequency was observed using pollen collected from the spikes 1 day after irradiation over that of 2 or 3 days after irradiation. More than 70% of the translocations detected in the M1 generation were transmitted to the BC1 through the female gametes. All translocations recovered in the BC1 generation were recovered in the following BC2, and BC3 generations. The transmission ability of different translocation types in different genetic backgrounds showed an order of ‘whole-arm translocation 〉 small alien segment translocation 〉 large alien segment translocation＇, through either male or female gametes, In general, the transmission ability through the female gametes was higher than that through the male gametes. By this approach, 14 translocation lines that involved different H. villosa chromosomes have been identified in the BC3 using EST-STS markers, and eight of them were homozygous.     

对水稻第9和第12染色体编号分歧的细胞学考证

在水稻细胞遗传研究中, 对于染色体编号有着较多的争议,这在几条长度较短的染色体上显得尤为突出。为有比较地研究这几条染色体在水稻染色体组中的正确编号,本研究以涉及两条较短染色体相互易位的易位杂合体RT9-12为材料,分析了易位系与普通品种日本晴减数分裂粗线期染色体的形态特征。结果表明,该易位系的易位染色体并非第9和第12染色体,而是第10和第11染色体,从而认为目前国际上统一编号的第9、12染色体,根据染色体的实际长度可能分别为第10、11染色体。 Abstract:Rice chromosomes in mitosis are usually too small to be identified clearly one from others.In recent years,pachytene chromosomes in meiosis have been in vestigated intensively for establishing unified numbering system.However,divergence in numbering system is still existing especially for some short chromosomes such as chromosome 9 and 12.In order to verify these chromosomes,a translocation line RT9-12 and a japonica variety Nipponbare were carefully investigated for all the chromosomes morphologically in late pachytene stage.It was found that the chromosomes involved in translocation were chromosome 10 and 11 in stead of chromosome 9 and 12 as being compared with the karyotype of Nipponbare.So we consider that the chromosome 9 and 12 in the present rice chromosome numbering system could be chromosome 10 and 11 according to their length,arm ratio and the relationship with nucleolus.     

赤链蛇染色体组型、C带和Ag-NORs的研究

以骨髓细胞为材料研究赤链蛇的染色体,结果表明该物种2n=46,由8对大型的和15对微小的染色体组成,AF=50.性染色体的大小介于3号和4号之间,为ZW型;8对大型染色体均显示着丝粒C带,1-6号还显示浅染端粒C带.W染色体为整条C带阳性;该物种一对NOR位于7号染色体近着丝粒区.不同地理分布群赤链蛇核型可能经历过Z与W染色体不等交换。 Abstract:The Karyotype,C-bands and Ag-NORs of Dinodon rufozonaturn (Cantor) reported is in this paper including the diploid number(2n=46)comprising 8 pairs of macro-and 15 pairs of microchromosomes,and AF=50 in the D.rufozonatum.The sex chromosome in size locates between the autochromosones No.3 and No.4,which belongs to ZW type.The C-banding technique revealed that the all macrochromosomes there are centromerc C band,the telomeric C band was only observed in Nos.1~6,while a whole W chromosome is constitutive heterochromatinization.Two NOR were observed on the pericentric of the No.7 chromosome.     

Cytogenetic and molecular identification of three Triticum aestivum-Leymus racemosus translocation addition lines

Chromosome 2C from Aegilops cylindrica has the ability to induce chromosome breakage in common wheat （Tritivum aestivum）. In the BC1F3 generation of the T. aestivum cv. Chinese Spring and a hybrid between T. aestivum-Leymus racemosus Lr.7 addition line and T. aestivum-Ae, cylindrica 2C addition line, three disomic translocation addition lines （2n = 44） were selected by mitotic chromosome C-banding and genomic in situ hybridization. We further characterized these T. aestivum-L, racemosus translocation addition lines, NAU636, NAU637 and NAU638, by chromosome C-banding, in situ hybridization using the A- and D-genome-specific bacterial artificial chromosome （BAC） clones 676D4 and 9M13; plasmids pAsl and pSc119.2, and 45S rDNA; as well as genomic DNA of L. racemosus as probes, in combination with double ditelosomic test cross and SSR marker analysis. The translocation chromosomes were designated as T3AS-Lr7S, T6BS-Lr7S, and T5DS-Lr7L. The translocation line T3AS-Lr7S was highly resistant to Fusarium head blight and will be useful germplasm for resistance breeding.     

Licheni Dell'A. O. I.

Riassunto

L'A. studia N. 87 entità di licheni raccolti nell'A. O. I. da ufficiali della Milizia Nazionale Forestale. Fra essi ci sono nuove per la scienza due specie: Chaenothecopsis africana, Theloschistes Sennii e 8 fra varietà e forme; molti sono nuovi per l'A.O.I. e per il Continente africano.