风毛菊属5种植物的核型分析

采用常规压片法,对风毛菊属(Saussurea)5种植物的染色体数目和核型类型进行分析。结果表明:大耳叶风毛菊(S.macrota)核型公式为2n=2x=26=10m+12sm+4st,属2A型;长梗风毛菊(S.dolichopoda)核型公式为2n=2x=26=14m+8sm+4st,属2A型;川陕风毛菊(S.licentiana)核型公式为2n=2x=28=12m+16sm,属2B型;杨叶风毛菊(S.populifolia)核型公式为2n=2x=28=6m+18sm+4st,属2B型;尾叶风毛菊(S.caudata)核型公式为2n=2x=30=14m+14sm+2st,属2A型。这5种风毛菊属植物中,除大耳叶风毛菊染色体数目和核型类型与前人报道的一致外,其余4种植物的染色体数目和核型类型均为首次报道,并在川陕风毛菊中发现1对B染色体。     

CHROMOSOME MORPHOLOGY IN THE GENUS SAMBUCUS

Two basic chromosome karyotypes were found in the genus Sambucus. Chromosome numbers were observed to be 2n = 38 for S. callicarpa, S. cerulea, S. glauca, S. kamtschatica, S. melanocarpa, S. mexicana, S. miquelli, S. sibirica, and S. sieboldiana and 2n = 36 for S. simpsonii and S. williamsii. Measurements of 18 karyotypes are presented. The major differences between the two basic chromosome karyotypes can be explained as the result of a mis-division of a metacentric chromosome giving rise to two telocentric chromosomes, thus reducing the number of metacentrics from five to four and increasing the chromosome number from 2n = 36 to 2n = 38. Observed chromosome aberrations and aneuploidy may result from unstable telocentric chromosomes.     

Diversified chromosomal characteristics in Centropyge fishes (Pomacanthidae, Perciformes)

We studied karyotypes and other chromosomal markers such as C-banded heterochromatin and Ag-stained nucleolus organizer regions (Ag-NORs), in seven Centropyge fishes (Pomacanthidae, Perciformes). These results revealed diversified chromosomal characteristics in Centropyge species. Three species had 2n = 48 chromosomes, whereas four species had 2n = 52 chromosomes. Fundamental numbers showed a large variation from 48 to 82, particularly in the species with 2n = 52 chromosomes. In all the species, Ag-NORs were located in a single chromosome pair and C-bands were mainly distributed in the centromeric regions of most chromosomes, as commonly seen in teleostean fishes. However, these chromosomal markers showed species-specific variations and provided us with useful information that could help us in understanding chromosomal evolution. On the basis of these chromosomal characteristics, we infer the process of chromosomal evolution, which according to us involves an increase in chromosome number from 2n = 48 to 2n = 52 through centric fission or other mechanisms, and in fundamental number through pericentric inversion. In particular, karyotypic evolution involving the increase in chromosome number is an unusual event in the evolution of higher teleostean groups. Handling editor: K. Martens     

Chromosome polymorphism in the ant,Pheidole nodus

A survey of chromosome polymorphism was made in populations of Pheidole nodus (Hymenoptera, Formicidae). A total of 1,666 males were collected from 11 localities in Japn. Four polymorphic karyotypes were observed: (1) n = 17 with 4 metacentrics (abbreviated as 4M), (2) n = 18(3M), (3) n = 19(2M) and (4) n = 20(1M). These differences are due to the Robertsonian type rearrangement. The karyotype 18(3M) is found in all the populations examined, but the others are more or less localized in their distribution. The 17(4M) appears mainly in Shikoku and the northern Kyushu populations, 19(2M) along the Pacific coast of Honshu, Shikoku and Kyushu, and 20(1M) in the eastern part of Honshu and Shikoku. This distribution pattern indicates that 18(3M) is the oldest, 19(2M) and 20(1M) are derived from 18(3M) by centric fission, and 17(4M) by centric fusion. The most probable mechanism of karyotype evolution in this species is considered to be the centric fission.     

Different rate of intrapopulation chromosome polymorphism in two species of Black Sea Blennies (Blenniidae,Pisces)

Somatic karyotypes in seven specimens of Blennius sanguinolentus include 22 subtelocentric and 26 acrocentric chromosomes, whereas one male has 2n=47=1M+22ST+24A: polymorphism is evidently a result of centric fusion of two acrocentrics. Blennius tentacularis is characterized by the availability of four karyomorphs out of which three coincide with karyotypes described earlier (Carbone et al., 1987). Karyttype-I consists of a 48 small uni-armed chromosome, but both karyotypes II and III with 2n=48 and 2n=47 respectively include one large acrocentric chromosome, and karyotype-IV has one large submetacentric out of the 47 chromosomes. Karyotypic variability of B. tentacularis is attributed either to polymorphism by 1–3 chromosome rearrangements or to availability of sex-determining mechanism, including the Y-autosome translocation. This diverse series of male karyomorphs may reflect the complicated behavioural structure.     

The unique genome of two-chromosome grasses <Emphasis Type="Italic">Zingeria</Emphasis> and <Emphasis Type="Italic">Colpodium</Emphasis>, its origin,and evolution

Chromosome C-banding and two-color fluorescent in situ hybridization (FISH) were used to compare the chromosomes, to identify the chromosomal localization of the 45S and 5S rRNA genes, and to analyze the sequences of internal transcribed spacers 1 and 2 (ITS1 and ITS2) of the 45S rRNA genes in the genomes of grasses Zingeria biebersteiniana (2n = 4), Z. pisidica, Z. trichopoda (2n = 8), Colpodium versicolor (2n = 4), and Catabrosella variegata (syn. Colpodium variegatum) (2 n = 10). Differences in C-banding pattern were observed for two Z. biebersteiniana accessions from different localities. Similar C-banding patterns of chromosomes 1 and 2 were demonstrated for the Z. pisidica and Z. biebersteininana karyotypes. Chromosome C banding and localization of the 45S and 5S rRNA genes on the chromosomes of the two Zingeria species confirmed the assumption that Z. pisidica is an allotetraploid with one of the subgenomes similar to the Z. biebersteiniana genome. ITS comparisons showed that the unique two-chromosome grasses (x = 2)—Z. biebersteiniana (2n = 4), Z. trichopoda (2n = 8), Z. pisidica (2n = 8), and C. versicolor (2n = 4), which were earlier assigned to different tribes of subtribes of the family Poaceae—represent two closely related genera, the genetic distance (p-distance) between their ITSs being only 1.2–4.4%. The Zingeria species and C. versicolor formed a common clade with Catabrosella araratica (2n = 42, x = 7) on a molecular phylogenetic tree. Thus, the karyotypes of Zingeria and Colpodium, which have the lowest known basic chromosome number (x = 2), proved to be monophyletic, rather than originating from different phylogenetic lineages.     

Two new karyotypes in the Peruvian owl monkey (Aotus trivirgatus)

The observation of remarkable karyotypic variation in owl monkeys (Aotus trivirgatus) stimulated us to study the chromosomal evolution of this New World genus. As an extension of this project, we examined the chromosome complement of a “phenotype-B” Aotus population from Peru. In addition to karyotype V(2n = 46), two new karyotypes with diploid numbers of 47 and 48 were identified. A G-band comparison of these karyotypes indicated that the chromosome number polymorphism in these Peruvian owl monkeys resulted from a single fusion or fission event involving a single metacentric and two acrocentric chromosome pairs. This mechanism is also known to be responsible for the chromosome number polymorphism in at least two other populations of phenotype B Aotus, one from Colombia and the other from Panama.     

Karyomorphological study of the Spiraea japonica complex (Rosaceae)

Reported in this paper is a karyomorphological study on one natural population of each of eight varieties in theSpiraea japonica complex. The interphase and mitotic prophase can be classified into the simple chromocenter type and the proximal type, respectively. The metaphase karyotypes of the eight varieties were formulated as follows:S. japonica var.japonica: 2n=18=14m+2sm+2st;S. japonica var.acuta: 2n=18=11m+4sm+3st;S. japonica var.incisa: 2n=18=12m+4sm+2st;S. japonica var.stellaris: 2n=18=15m+1sm+2st;S. japonica var.acuminata: 2n=18=14m+2sm+2st;S. japonica var.ovalifolia: 2n=18=10m+2sm+2st+4t;S. japonica var.glabra: 2n=18=10m+4sm+4st;S. japonica var.fortunei: 2n=36=17m+16sm+3st. Karyomorphological study reveals that the chromosome numbers within the complex are stable, and that karyomorphological divergence between the varieties lies mainly in chromosome size and organization. Based on the karyomorphological data and geographical distribution of the complex, the differentiation pattern as well as evolutionary mechanism of the complex is evaluated.     

青海四种雏蝗染色体核型的比较分析

采用常规染色体制片方法对雏蝗属的褐色雏蝗Chorthippusbrunneus(Thunb .) ,异色雏蝗C .big uttulus(Linnaeus) ,小翅雏蝗C .fallax(Zub .) ,青藏雏蝗C .qingzangensis(Ying)的染色体核型进行分析 ,结果 :染色体数目均为 2n(♂ ) =1 7=1 6+XO ;常染色体类型为两类 ,中着丝点染色体 (m ,6条 )和端着丝点染色体 (T ,1 0条 ) ;性染色体类型为端着丝点。褐色雏蝗、异色雏蝗和青藏雏蝗的核型公式和染色体的相对长度组成为K( 2n ,♂ ) =1 7=6m +1 1T =6L +6M +4S +XO ,K( 2n ,♀ ) =1 8=6m +1 2T =6L +6M +4S +XX ;小翅雏蝗的为K( 2n,♂ ) =1 7=6m +1 1T =6L +4M +6S +XO ,K( 2n ,♀ ) =1 8=6m +1 2T =6L +4M +6S+XX。褐色雏蝗性染色体中部有次缢痕。染色体臂数 4种均为NF =2 3(♂ ) ,2 4 (♀ )。     

Karyotypes and Giemsa C-banding patterns of Zebrina pendula, Z. purpusii and Setcreasea purpurea, compared with those of Tradescantia ohiensis.

It has been proposed that the genera Zebrina and Setcreasea of the family Commelinaceae should be united and reunited, respectively, with the genus Tradescantia, mainly based on morphological studies. In the present study, karyotypes and Giemsa C-banding patterns in the root-tip cells of three Zebrina and two Setcreasea clones were analyzed, and were compared with those of a triploid Tradescantia clone. Z. pendula and Z. purpusii (both 2n = 24) were found to have similar karyotypes (4 M + 6 ST + 14 T; M = meta-, ST = subtelo-, T = telocentric chromosomes), while Z. pendula cv Quadricolor (2n = 23) had a unique karyotype (6 M + 5 ST + 11 T + 1 SA; SA = short acrocentric chromosome). The only clear difference between Z. pendula and Z. purpusii was that one and two subtelocentric chromosomes, respectively, had satellites at the short arms. Two clones of S. purpurea (2n = 24) had karyotypes (8 M + 8 M' + 8 SM; M' = nearly meta-, SM = submetacentric chromosomes) similar to each other. T. ohiensis (2n = 18) had a symmetric karyotype (9 M + 9 SM) consisting of larger chromosomes than S. purpurea. Many clear Giemsa C-bands were detected, in addition to centromeric bands in all chromosomes of all clones. Z. pendula and Z. purpusii commonly had single clear interstitial bands in eight telocentric chromosomes each, but they also had unique telomeric and other interstitial bands, respectively. Z. pendula cv Quadricolor had a unique banding pattern, i.e., satellite bands in the unique short chromosome, telomeric bands at the long arms of all metacentric chromosomes, and single interstitial bands in six telocentric chromosomes. Two clones of S. purpurea had telomeric bands at many chromosome arms and satellite bands in two nearly metacentric and one submetacentric chromosomes, but some differences were found between them. On the other hand, all the chromosomes of T. ohiensis had telomeric bands at both arms, and three submetacentric chromosomes had satellite bands. These result prove structural differentiation of chromosomes occurred among the clones, especially in Zebrina, and show that S. purpurea is relatively close to T. ohiensis, while Zebrina is obviously distant from the other two genera. Therefore, there remains a question cytologically at least for uniting Zebrina with Tradescantia.     

Further survey of chromosomal polymorphisms in the freshwater planarian Polycelis auriculata

Although the chromosomal number of Polycelis (Seidlia) auriculata Ijima et Kaburaki is basically 2n = 6, this species shows remarkable chromosomal polymorphisms in different populations. Among worms collected at 30 stations in the central part of Japan's Main Island and in Hokkaido, we found five new karyotypes, considered to be variations of tetraploidy and diploidy: 4n?fis¹. + 1 = 3SM + 2A + 3T₁ + 2T₂ + 4M = 14, 4n?fis².(B) = 2SM + 2A + 4T₁ + 2T₂ + 4M + (0?2B) = 14 –16, 4n?fis². + 1 = 2SM + 2A + 4T₁ + 2T₂+5M= 15, 4n?fis².?2 = 2SM + 2A + 4T₁ + 4M = 12, and 2nM- = 2SM + 2A = 4 (where SM = submetacentric; A = acrocentric; T₁ and T₂ = telocentric; M = metacentric; B = B-chromosome; fis¹. and fis². = occurrence of one or two centric fissions, respectively; and M- = deletion of a metacentric chromosome). These karyotypes exist singly in one individual or as various mixoploids within the same individual. No individual having only karyotype 2nM- has yet been found. This brings the total number of known karyotypes in P. auriculata to 17; these can be arranged in an order that we believe reflects their evolution.     

Chromosome evolution in pseudoxyrhophiine snakes from Madagascar: a wide range of karyotypic variability

In this first cytogenetic survey on the lamprophiid snake subfamily Pseudoxyrhophiinae, we studied the karyology of ten snake species belonging to seven genera from Madagascar (Compsophis, Leioheterodon, Liophidium, Lycodryas, Madagascarophis, Phisalixella and Thamnosophis) using standard and banding methods. Our results show a wide range of different karyotypes ranging from 2n = 34 to 2n = 46 elements (FN from 40 to 48), with nucleolus organizer regions (NORs) on one (plesiomorphic) or two (derived/apomorphic) microchromosome pairs, and W chromosome at early or advanced states of diversification from the Z chromosome. The observed W chromosome variations further support the most accepted hypothesis that W differentiation from the Z chromosome occurred by progressive steps. We also propose an evolutionary scenario for the observed high karyotype diversity in this group of snakes, suggesting that it is derived from a putative primitive pseudoxyrhophiine karyotype with 2n = 46, similar to that of Leioheterodon geayi, via a series of centric fusions and inversions among macrochromosomes and translocations of micro‐ either to micro‐ or to macrochromosomes. This primitive Pseudoxyrhophiinae karyotype might have derived from a putative Lamprophiidae ancestor with 2n = 48, by means of a translocation of a micro‐ to a macrochromosome. In turn, the karyotype of this lamprophiid common ancestor may have derived from the assumed primitive snake karyotype (2n = 36 chromosomes, with 16 biarmed macro‐ and 20 microchromosomes) by a series of centric fissions and one inversion. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 450–460.     

Karyotype evolution by centromeric fission inZamia (Cycadales)

The chromosome numbers of several species ofZamia from Mexico are reported.Z. paucijuga, distributed from central Oaxaca to Nayarit, has been found to have 2n = 23, 25, 26, 27 and 28. 2n = 28 is the highest chromosome number yet found in the cycads. Karyotypes of this species differ principally in the number of telocentric and metacentric chromosomes present in each; 2n = 23, 25, 26, 27 and 28 were found to have 5, 3, 2, 1 and 0 metacentric and 8, 12, 14, 16 and 18 telocentric chromosomes, respectively.Z. fischeri has been found to be 2n = 16,Z. furfuracea andZ. loddigesii 2n = 18.Zamia paucijuga on the basis of morphological and ecological characteristics, is considered to be an advanced member of this genus. Chromosome and karyotype evolution inZ. paucijuga may have occurred by centromeric fission of metacentric chromosomes; the karyotypes ofZ. paucijuga are strongly asymmetrical, suggesting that they evolved recently.     

Multiplication of 28S rDNA and NOR activity in chromosome evolution among ants of the Myrmecia pilosula species complex

Chromosomal localization of rDNA in samples of five taxa of the Myrmecia pilosula species complex (Hymeoptera: Formicidae: Myrmeciinae) with 2n=3 (M. croslandi), 8 (M. imaii), 10 (M. banksi), 18 (M. haskinsorum), and 27 (M. pilosula) was carried out by fluorescence in situ hybridization (FISH) using cloned M. croslandi rDNA (pMc.r2) including the coding region for 28S rRNA. Results show that (1) the 28S rDNA in the genome of these ants is repetitive and is localized in pericentromeric C-bands, (2) the number of chromosomes carrying rDNA is two in M. croslandi, M. imaii and M. banksi, six in M. haskinsorum and ten in M. pilosula, and (3) only one or two clusters of rRNA genes generate nucleoli in each species. We suggest that the rDNA in the ancestral stock of the M. pilosula complex was localized originally in a pericentromeric C-band, and multiplied by chance with time during saltatory increases in C-banding following episodes of centric fission. Most rDNA multiplied on various chromosomes seems to be inactivated and eliminated from the genome, together with C-bands, by -inversion or centric fusion, with the remnant rDNAs dispersed in the genome by centric fission and -inversion.     

基于荧光原位杂交技术的紫薇属植物核型分析

以紫薇(Lagerstroemia indica)、尾叶紫薇(L.caudata)、屋久岛紫薇(L.fauriei)和福建紫薇(L.limii)4种紫薇属植物为材料,利用染色体荧光原位杂交技术(FISH)获得了4种紫薇属植物的有丝分裂中期染色体FISH图及核型参数,分析了45SrDNA在紫薇属植物染色体上的数量和分布特点。结果表明,4种紫薇属植物染色体上均具有1对45SrDNA杂交位点,位于较长染色体短臂的近端部,紫薇、尾叶紫薇、屋久岛紫薇和福建紫薇的核型公式分别为2n=48=2M+24m+22sm、2n=48=30m+18sm、2n=48=2M+20m+26sm和2n=48=2M+32m+14sm,均为2A型。该研究首次获得了紫薇属植物45SrDNA荧光原位杂交核型,为紫薇属植物亲缘关系研究和细胞生物学研究提供了分子细胞学依据。     

Cytotaxonomic analysis of the Himalayan species of the genusTorilis (Apiaceae)

Chromosome studies of four HimalayanTorilis species reveal a remarkable interand intraspecific differentiation of chromosome numbers and karyotypes:T. arvensis (2n = 12),T. leptophylla (2n = 12),T. Stocksiana (2n = 36) andT. japonica (2n = 16). Base numbers inTorilis are x = 6, 8, 9 and 11.     

獐牙菜属5种植物的核型研究

首次报道了中国５种獐芽菜属植物的染色体数目和核型。它们染色体中期核和相对长度组分分别是：四数獐牙菜为２ｎ＝１４＝４ｍ＋８ｓｍ＋２ｓｔ＝２Ｌ＋６Ｍ２＋４Ｍ１＋２Ｓ;华北獐牙菜２ｎ＝２８＝１２ｍ＋１４ｓｍ＋２ｓｔ＝６Ｌ＋８Ｍ１＋＋６Ｓ;二叶獐牙菜为２ｎ＝２８＝１４ｍ＋４ｓｍ＋１０ｓｔ＝２Ｌ＋１４Ｍ２＋１０１＋ｓＳ;抱茎獐 菜为２ｎ＝６ｍ＋１２ｓｍ＋２ｓｔ＝８Ｍ２＋１２Ｍ;浙江獐牙菜为２ｎ＝２０＝８ｍ＋     

华南地区3种兔儿风属植物(菊科-帚菊木族)的细胞学研究

首次报道了华南地区兔儿风属(Ainsliaea DC.)(菊科-帚菊木族Asteraceae-Pertyeae)3种植物共4个居群的染色体数目和核型。其中长穗兔儿风(A.henryi Diels)的染色体数目为2n=24,核型公式为2n=16m+8sm;三脉兔儿风(A.trinervis Y.C.Tseng)的染色体数目为2n=26,核型公式为2n=16m+10sm;莲沱兔儿风(A.ramosa Hemsl.)2个居群的染色体数目均为2n=26,核型公式为2n=26=22m+4sm。所有居群的染色体由大到小逐渐变化,核型没有明显的二型性。这些结果表明兔儿风属植物确有x=12和x=13两个基数,其中x=13可能是该属的原始基数。     

Karyotype variability in species of the genus Zephyranthes Herb. (Amaryllidaceae�CHippeastreae)

In this work, the cytotaxonomic implications of the chromosomal characterization of cultivated and native Zephyranthes species described in northeastern Brazil were studied. All individuals had karyotype formed by a set of metacentric chromosomes, in addition to submetacentric and acrocentric chromosomes. In Zephyranthes robusta, 2n?=?12 was observed and karyotype with formula?4M?+?2SM in somatic cells, representing the most symmetric karyotype among the investigated species. Z.?sylvatica showed three different chromosome complement numbers: 2n?=?12 with formula?1M?+?5SM, 2n?=?12?+?1B with 1M?+?5SM?+?(1B), and 2n?=?18 formed by cracks. The cultivated species Z.?rosea Lindl. presented 2n?=?24 with 4M?+?7SM?+?1A, however Z.?grandiflora Lindl. showed the same chromosome number with 2M?+?5SM?+?5A. Zephyranthes aff. rosea Lindl. presented 2n?=?25 with one small metacentric forming a crack in the fourth metacentric pair. Z.?brachyandra has 2n?=?24?+?(1B) and formula?4M?+?3SM?+?5A?+?(1B). Z.?candida Herb. presented 2n?=?38 and karyotype formula?9M?+?10SM. In Habranthus itaobinus numerical variation was observed, with the majority of populations showing a chromosome complement composed of 2n?=?44?+?1B with 5M?+?12SM?+?5A?+?(1B), or 2n?=?44?+?3B in a single population. Mechanisms involved in the formation of these karyotypes from chromosomal imbalance data are discussed. Taken together, data from this study only partially confirm previous counts for epithets and further enhance the cytological variability data previously reported for the genus.     

Chromosome investigations in annual Medicago species (Fabaceae) with emphasis on the origin of the polyploid Medicago rugosa and M. scutellata

Chromosome number variations play an important role in the genus Medicago. In addition to polyploidy there are cases of dysploidy as evidenced by two basic numbers, x = 8 and x = 7, the latter limited to five annual species having 2n = 14. Annuals are diploid with the exception of Medicago scutellata and Medicago rugosa which have 2n = 30 and are considered the result of crosses between the 2n = 16 and 2n = 14 species. However, this hypothesis has never been tested. This study was carried out to investigate the 2n = 14 and 2n = 30 karyotypes and verify the allopolyploid origin of M. scutellata and M. rugosa. Fluorescence in situ hybridization (FISH) of rDNA probes and genomic in situ hybridization (GISH) were performed. FISH showed that all five diploids with 2n = 14 have one pair of 45S and one pair of 5S rDNA sites. M. scutellata displayed four sites of 45S and four sites of 5S rDNA, while in M. rugosa only one pair of each of these sites was found. GISH did not produce signals useful to identify the presumed progenitors with 14 chromosomes. This result suggests alternative evolutionary pathways, such as the formation of tetraploids (2n = 32) and subsequent dysploidy events leading to the chromosome number reduction.