Étude comparée de Saga rhodiensis Salfi 1929 et Saga natoliae Serville 1839 (Orthoptera: Tettigoniidae)

Saga rhodiensis se révèle très proche de S. natoliae et ces deux taxons s’acceptent mutuellement pour la copulation. En outre, ils constituent, avec S. hellenica, un groupe assez homogène au niveau chromosomique. Sur le plan morphologique S. hellenica se distingue aisément des deux autres espèces, et aucun accouplement croisé n’a pu aboutir dans nos élevages. La découverte d’individus femelles de S. natoliae présentant les critères morphologiques de S. rhodiensis bien audelà de l’aire de distribution actuellement connue, nous interroge sur la pertinence de ces critères. Des investigations complémentaires sont nécessaires pour préciser le statut exact de S. rhodiensis.     

10种梅花品种及其3种近缘种的核型分析

采用压片法,对10种梅花品种及其3种近缘种杏、山杏和紫叶李进行了核型分析。结果表明:10种梅花品种及杏、山杏和紫叶李均为二倍体2n=2x=16,核不对称系数为55.17%~61.71%,核型类型有1A、1B、2B等3种类型,所有品种或种的核型都由其中部或近中部的着丝点染色体组成。‘丰后’和‘俏美人’等2个杂种品种染色体信息介于梅花与杏、山杏和紫叶李之间。     

苜蓿属3种不同花色基因型的染色体核型分析

基于形态学的显著差异,对紫花苜蓿(Medicago sativa L.)、黄花苜蓿(Medicago falcata L.)和白花苜蓿(Alfalfa with Cream flower)进行染色体核型分析,结果表明,3种类型的苜蓿材料在染色体核型方面有显著差别,白花苜蓿和黄花苜蓿都是随体染色体,其中,黄花苜蓿有2条为端部着丝点染色体,其核型公式分别为:紫花苜蓿2n=4x=24m+8sm、黄花苜蓿2n=4x=24m+6sm+2T(SAT)、白花苜蓿2n=4x=24m+8sm(SAT)。紫花苜蓿与白花苜蓿的染色体具有89%的相似性,只是在紫花苜蓿7号染色体和白花苜蓿15号染色体存在随体有无的区别;黄花苜蓿染色体具有独特性,显著区别于紫花苜蓿和白花苜蓿,但从其19号染色体来看,参与了紫花苜蓿或白花苜蓿的构建;白花苜蓿15号随体染色体与黄花苜蓿25号随体染色体和紫花苜蓿7号染色体有高度的相似性,但也存在随体有无的区别。     

Rapid method to obtain high quality nuclear and chromosome images directly from living cells in the Characeae

This study focused on a method based on the capacity of cationic dyes to stain only the nucleus and chromosomes in cells subjected to either acid or alkaline hydrolysis. The method and the squash were optimized for the Characeae and were described in detail. Nuclei from vegetative shoot apices and antheridial filament cells of unfixed, fixed and herbarium material of Nitella opaca were investigated using the Azure A or Toulidine Blue stains. Comparisons with some other staining methods, used in the previous studies, were also reported. The Azure A/Toulidine Blue method is useful to obtain clear images of chromosome morphology comparable or higher to that obtained with Feulgen or Aceto‐Orcein. It requires little time and a less complicated procedure in comparison with other staining methods.     

Cytogeography and chromosomal variation of the endemic East Asian herb Lycoris radiata

Information on the spatial distribution of cytotypes and karyotype variation in plants is critical for studies of the origin and evolution of polyploid complexes. Here, the spatial distribution of cytological races and intraspecific variation in the karyotype of Lycoris radiata, an endemic species to East Asia, is investigated. Conventional karyotype analysis methods were used to determine ploidy level and karyotypical characteristics in 2,420 individuals from 114 populations of L. radiata nearly covering the whole distribution areas in China. Of 114 populations studied, 52 (45.61%), 58 (50.88%), and 4 (3.51%) are diploid, triploid, and mixoploid populations, respectively, with 1,224, 1,195, and 1 individuals being diploid, triploid, and tetraploid, respectively. The triploid possesses a much wider distribution range than the diploid, with the former almost occupying the entire range of this complex species in East Asia and the latter distributing in the middle and east regions of China. Triploids tend to occur at high altitudes, and the relationship between the ploidy and altitude is significantly positive but low (r² = 0.103, p < 0.01). About 98.6% of examined bulbs have a common karyotype consisting of 22 or 33 acrocentric (A) chromosomes. Some aberrant chromosomes which should be generated from A‐type chromosome have been found including metacentrics (m), small metacentrics (m′), and B‐type chromosome. The results can provide a fundamental cytogeographic data for further studies on the evolutionary origins and adaptive divergences of polyploids, especially the triploid, within L. radiata using molecular and/or ecological methods in the future.     

Cytogenetic identification of genomic elements of brook trout (Salvelinus fontinalis) in the karyotype of Arctic char (Salvelinus alpinus) from the aquaculture broodstock

Growing interest of Arctic char (Salvelinus alpinus) aquaculture in Europe, and the fact that it can easily hybridize with brook trout (Salvelinus fontinalis) resulting in fertile progeny, led us to investigate fish from the farmed stocks. Chromosomes of sampled Arctic char were examined using conventional and molecular cytogenetic (FISH) techniques in order to determine possible contamination of genomic elements of brook trout. Investigated fish possessed karyotypes composed of 80–82 chromosomes and up to three chromosome fragments. Using staining methods and FISH approach enabled identification of the brook trout chromosomes in the eight out of twenty‐two examined Arctic char. Specific location of AT‐, GC‐ positive and NOR sites observed on chromosomes as well as chromosome fragments in the karyotypes of several individuals points on past chromosomal rearrangements in fish from examined broodstock. Based on our results, it may be assumed that individuals with the brook trout genomic elements, although phenotypically identified as Arctic chars, were hybrids. Our results highlights that special care should be taken to protect gene pools of brook trout and Arctic char in farms where both species are cultured.     

Cytology and taxonomy of Coptis teeta Wall.(Ranunculaceae)

Cytological investigations of 13 natural populations of Coptis teeta indicated that the species has a somatic number of 18 chromosomes which form nine homomorphic pairs. The species did not possess any supernumerary chromosomes. The chromosome number, size and morphology were similar in all populationS. Based on the taxonomic studies the 13 natural populations are grouped into two well-defined subspecies, teeta and lohitensis, for which a key is provided.     

Genome size and chromosomes in marine sponges [Suberites domuncula,Geodia cydonium]

The genome size of the marine sponges Suberites domuncula and Geodia cydonium has been determined by flow cytofluorometric analysis using diamidino-phenylindole [DAPI]. Using human lymphocytes as reference the amount of DNA in cells from S. domuncula has been determined to be 3.7 pg and that of G. cydonium 3.3 pg. While no chromosomes could be identified in G. cydonium, the karyotype of the Suberites domuncula is 32 chromsomes in the diploid state. The size of the chromosomes was between 0.25 and 1.0 μm. No pronounced banding pattern was visible.     

Genetic differentiation of house mice in the fauna of the former U.S.S.R.: results of cytogenetic studies

A cytogenic study of nearly 200 house mice (Mus musculus sensu stneto) and aboriginal mice (Mus hortulanus, Mus abbotti) of the subgenus Mus was carried out. Mice were sampled from most localities in the former U.S.S.R., from the western borders to the Far East, and it was shown that it is possible to use cytogenetic markers to classify the species and rare subspecies of the subgenus. Such markers included the characteristic morphology of the sex chromosomes and the pattern of distribution of the C-heterochromatin in the karyotype. Thus, the aboriginal mice, together with M. spretus , are characterized by a significant reduction in the size of the Y chromosome. In addition, the variant of the X chromosome (so called 'molossinus' lype) previously only observed in Japanese M. in. molossinus was found in all the Mus musculus sampled from the fauna of the former U.S.S.R. Another type, the so called 'domeslicus' is a plesiomorphic variant of the X chromosome which is normally found in M. domestuus. M. hortulanus, M. abbotti and possibly in M. spretus. The presence of the common variant X chromosome in the house mice of the various subspecies in the fauna of the former U.S.S.R., Mongolia (raddei) and Japan (molossinus) provides the basis for the integration of Asian house mice into the one species, At. musculus sensu stricto. The problems of morphology, ecology and systematics of the mouse fauna of the former U.S.S.R. are also discussed with special attention being paid to the studies of the so called 'wagnen' form.     

禺毛茛及其复合体种间亲缘关系形成研究

在Tamura M.,Okada及廖亮研究的基础上,通过禺毛茛复合体(禺毛茛R.cantoniensis 4x,卷喙毛茛R.sileri folius var.silerifolius 2x,长花毛茛R.sileri folius var.dolicathus 2x,茴茴蒜R.chinensis 2x,扬子毛茛R.sieboldii 6x及8x)的核型分析,结合地球环境的演变历史,进一步研究了禺毛茛的形成方式和时间,并对禺毛茛复合体种间亲缘关系的形成进行了探讨,为毛茛属系统进化研究提供资料。