Pair Of Satellited Chromosomes Research Articles

Karyotype Analysis in Ten Taxa of <i>Tanacetum</i> L. (Asteraceae) from Turkey

The chromosome number and karyotype analysis of ten taxa of genus Tanacetum found native to Turkey were examined in detail. Somatic chromosome numbers were determined as follows: 2n=18 in T. balsamitoides Sch.Bip., T. parthenifolium Sch.Bip., T. zahlbruckneri (Náb.) Grierson, T. densum (Labill.) Sch.Bip. ssp. laxum Grierson, T. densum (Labill.) Sch.Bip. ssp. amani Heywood, T. argenteum (Lam.) Willd. ssp. argenteum, T. tomentellum (Boiss.) Grierson, 2n=36 in T. nitens (Boiss. & Noë) Grierson, T. polycephalum Sch.Bip. ssp. argyrophyllum (K.Koch) Podlech, T. abrotanifolium (L.) Druce. It was observed that chromosomes of Tanacetum taxa, of which karyotype analyses were examined, have generally median (m), submedian (sm), and rarely median point (M), subterminal (st) centromeres. In T. parthenifolium, T. nitens, T. abrotanifolium and T. argenteum ssp. argenteum; one pair of satellite chromosomes was observed.

Inter-specific hybridization of Alnus rubra and Alnus rhombifolia: preliminary report of a new taxon and DNA marker resources for bioenergy feedstock production

Exploratory hybridization of red alder (Alnus rubra Bong.) and white alder (Alnus rhombifolia Nutt.) was conducted to initiate a long-term investigation into the inter-specific taxon’s potential for biomass production. Red alder selections originated in stands west of Oregon’s Cascade Mountains, while white alder came from provenances west and east of the Cascades. White alder’s heretofore unknown chromosome number was determined equal to red alder (2n = 2x = 28) and included a pair of satellite chromosomes. An experimental crossing technique was proven, establishing the species’ reproductive affinity for the first time. Hybridization was substantially more productive when red alder served as the female parent as opposed to white alder. Hybridity was confirmed using four species-specific SSR markers developed from transcriptome resources for identifying sib relationships in domesticated populations. To begin a description of the inter-specific taxon, hybrids and their open-pollinated siblings were assessed at ages four through six for morphological and phenological traits and carbon and nitrogen isotopic ratios in a field planting in western Washington, USA. Principal component analysis of quantitative leaf and internode morphologies showed that red alder and hybrid alder are relatively comparable and both are distinct from white alder. Qualitative differences in leaf morphology are more diagnostic with inter-specific hybrids often intermediate to red and white alder. Principal coordinate analysis of molecular data cleanly separated the three taxa. Plans for continued investigation of the taxon as a biomass crop species are discussed including a potential role for inter-specific hybrids in adapting red alder to the effects of climate change.

Karyological studies of two hot chilli pepper cultivars from two different geographical regions of India: Bhut jolokia, Capsicum chinense Jacq. and Bullet Lanka, Capsicum annuum L.

The present paper deals with the detailed karyological studies of two hot chilli cultivars of India; one is world’s third hottest chilli Bhut jolokia (BJ) [Capsicum chinense Jacq. cultivar] collected from the hilly area of North-East India, and another is Bullet Lanka (BL) [Capsicum annuum L. cultivar] from plains of West Bengal. Comparative study showed that there was no difference in the chromosome count (2n = 24), but significant differences in chromosome characteristics were found between these two species. All 24 chromosomes of both species are metacentric with full symmetric karyotype. Both species have mono-modal chromosome with longest to shortest 5.75–4.60 µm in BJ and 8.91–6.02 µm in BL. The total chromosome length (TCL) of the haploid complements of BJ and BL are 62.56 and 87.36 μm, respectively. The total form percentage (TF %) of BJ and BL are 47.34 and 47.68 %, respectively. A pair of satellite (SAT) chromosomes with prominent secondary constriction is present in BL, but BJ does not contain any SAT chromosome. Thus, from the karyotype features, both BJ and BL exhibit close relationships which point out their probable origin from a common ancestor. Overall, the TF % and the TCL of BL was greater than BJ; indicating BL is evolutionarily slightly more advanced than BJ.

Karyological studies on the annual members of the genusCarduusL. (Asteraceae, Cardueae) from Turkey

The somatic chromosome numbers and detailed morphometric properties of eight of the nine annual Turkish Carduus L. taxa were examined. The somatic chromosome numbers were 2n = 2x = 22 in C. rechingerianus Kazmi; 2n = 2x = 28 in C. argentatus L., C. acicularis Bertol. and C. pycnocephalus L. subsp. albidus (M. Bieb.) Kazmi; 2n = 2x = 34 in C. pycnocephalus subsp. arabicus (Jacq. ex Murray) Nyman and subsp. breviphyllarius P. H. Davis; 2n = 2x = 50 in C. nervosus K. Koch.; and 2n = 2x = 62 in C. pycnocephalus subsp. pycnocephalus. Karyotype analysis indicated that chromosomes of the Carduus taxa generally have centromere median region (m), submedian region (sm), and rarely median point (M) of the chromosome. A pair of satellite chromosomes (sat-chromosome) was observed in C. pycnocephalus subsp. breviphyllarius. The findings for each of the analysed taxa are compared with the results of previous studies. The chromosome number and morphology of C. nervosus, C. rechingerianus, C. argentatus, C. pycnocephalus ...

Meiotic behaviour and karyotype features of endangered endemic fodder speciesHedysarum perrauderianum(Fabaceae) in some populations from Algeria

The Mediterranean basin is considered to be one of the 33 mega biodiversity hotspots with the greatest number of endemic plants. This region has been exposed to a prolonged anthropogenic influence rendering its biodiversity prone to a rapid change. The first cytogenetic data are presented for Hedysarum perrauderianum Coss. and Durieu (Fabaceae), an endangered stenoendemic fodder species from Algeria. Karyotype features, heterochromatin organization, physical mapping of rRNA genes and meiotic behaviour were studied in six native populations. The transcriptional rDNA activity was evaluated by nucleoli number. The tetraploid chromosome number 2n = 4x = 32 was found in all populations studied. However, in two roadside populations we observed cells of the same individuals that had 32 and 18 chromosomes. Constitutive heterochromatin is mainly present in intercalary and telomeric positions. Four strong GC-rich DNA bands situated on two pairs of satellite chromosomes are colocalized with 18S-5.8S-26S rDNA loci. S...

A Comparative Study of Karyomorphology among Three Populations of Garcinia indica (Clusiaceae) (Thomas-Dupetite) Choisy

Garcinia indica is a tree species of the family Clusiaceae. This species is endemically distributed only in Ratnagiri and Sindhudurga district of Maharashtra. Plants collected in particularly Dive Agar and Sawantwadi show morphological variations. Mitotic chromosomes from three different population from the Konkan region were studied using propionic orcein stain. Chromosome numbers 2n = 54 is reported for all the populations. Three populations differed from each other in some aspects. Karyotype analysis showed that Deorukh population from Ratnagiri region showed one pair of satellite and one pair of secondary constrictions while Otawane population from Sawantwadi showed one satellite chromosome but differ in pattern of secondary constriction. Third, Diveagar population from Raigad district showed three pairs of satellite chromosomes and one pair of secondary constriction. So, it can be concluded that, plants from Bapat Garden of Dive Agar and Otawane region can be considered as cytotypes.

Karyotype analysis and meiotic behaviors of Ducrosia anethifolia: The first case study

The medicinal plant Ducrosia anethifolia (DC) Boiss is an annual herb of the Apiaceae family. It originated from Iran and it is used to treat headache and backache in traditional medicine. Mitotic study and meiotic behavior of chromosomes are presented for the first time for D. anethifolia in this study. D. anethifolia possessed n = 11 (2n = 2x = 22) chromosome number forming mainly both rod and ring bivalents with some amount of quadrivalents and univalents. Karyotype analysis according to Stebbins categories, placed chromosomes of this plant in symmetric class of 2A, indicating a symmetric karyotype. The types of chromosomes were metacentric and submetacentric with one pair of satellite chromosomes. A variety of abnormal chromosomal behaviors including chromosomal stickiness, bridge, laggards, micronucleus, mass chromatin and early chromosome migrations were observed, albeit with low frequency. Tetrads with four equal-sized cells were considered normal and any deviation as abnormal. Stain-ability of pollens as an estimation of their fertility was ninety-seven percent. In this study we had few meiotic abnormalities and, as a consequence, a high pollen fertility. Well-filled pollen grains with stained nuclei were regarded as apparently fertile while shriveled, smaller microspores and unstained pollen were counted as sterile. The study reveals that meiosis in this species is normal, with high meiotic index and regular bivalent formation in most studied cells. Key words: Ducrosia anethifolia, karyotype, meiosis, pollen fertility.

Karyological characterisation of four American species of Crotalaria (Leguminosae: Papilionoideae) by the splash method

The karyotypes of Crotalaria juncea L., C. sagittalis L. (sect. Calycinae Wight & Arn.), C. mollicula Kunth and C. pumila Ortega (sect. Crotalariae Baker) were obtained by a surface-spreading and air-drying method (splash). All species have chromosome numbers based on x = 8 (2n = 16, 32). Chromosomes are metacentric (m) or submetacentric (sm), with one pair of satellite-chromosomes per complement. Although similar, the karyotypes are not particularly uniform, supporting the view that inter-specific differences of karyotypes can be used in species characterisation. There is sufficient evidence to show that large structural chromosome changes and hybridisation are significant in the diversification of this genus, particularly in the New World.

Karyological studies on eight species of Onobrychis genus in Turkey

This study used karyological techniques to determine the chromosome numbers and morphology of eight species of Onobrychis L. (O. caput-galli (L.) Lam, O. aequidentata (Sibth. & Sm.) d’ Urv, O. fallax Freyn & Sint. var. fallax, O. lasiostachya Boiss, O. viciifolia Scop., O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu, O. hypargyrea Boiss. and O. cappadocica Boiss.). The results of this study determined the chromosome numbers of O. cappadocica as 2n = 16; O. viciifolia as 2n = 28 and the other species as 2n = 14 The karyotypes of species consisted of median-centromeric (m) or submedian-centromeric (sm) chromosomes. However, O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu was found to have only the median-centromeric (m) chromosomes. According to the results of the present study, of the eight Onobrychis taxa, only O. hypargyrea has a pair of satellite chromosomes (sat-chromosome). Furthermore, this study detected karyotype asymmetry.

English

In order to study the morphological and cytological variation among Iranian nativeIrises, first, morphological traits were analyzed in order to clarify taxonomic relationships among taxa and validity of diagnostic characters. Floral and vegetative characters were measured in 54 plant samples belonging to five species during peak of the flowering season in 2008. Analysis of variance showed significant differences. Result of analysis shows that the most variation coefficient belongs to leaf width. Correlation of coefficients defined between the date of the first blooming of the flowers and the date of the least blooming of the flowers, flowers surface and diameter had the positive and significant correlation. Factor analysis showed that only three factors define almost near to 92% variance among characters. Secondly, in cytological variation each species showed different karyotypic formula such as 2n = 2sm+ 14st+4t for Iris meda, 2n = 8m + 16sm + 20st with one pair of terminal satellite chromosomes for Iris caspica, 2n = 26m + 18sm for Iris spuria, 2n= 14m + 12sm + 8st with one pair of terminal satellite chromosomes for Iris pseudacorousand 2n= 8m + 20sm + 20st for Iris germanica. This is the first karyotypic report in I. caspica, I. spuria and I. meda species in Iran. The results seemed to provide enough genetic evidence to identify each species and useful data to clarify the interspecific relationships among Iranian native Iris species.   Key words: Iris, karyotype, Iranian native, chromosome analysis, genome.

Genome size and cytogenetic characterization of three Algerian Retama species

Thirty-three populations belonging to the three Retama species, Retama monosperma, Retama raetam and Retama sphaerocarpa, were collected to study species differentiation using flow cytometry for 2C DNA assessment and molecular cytogenetics for karyotype organisation. All were 2n = 48. Genome size ranged from 1.76 to 1.97 pg and revealed significant intraspecific variation correlated to the geographic distribution of the populations. The number and position of the two ribosomal gene families 5S and 45S were determined by fluorescent in situ hybridization, revealing chromosome reorganisation between species. In R. raetam and R. monosperma, the minor 5S loci co-localised with 45S on the satellite chromosome pair. Fluorochrome banding identified GC- and AT-rich DNA regions. In R. monosperma a unique chromomycin positive GC-rich band was observed associated with the secondary constriction. In contrast, an original pattern showing two chromomycin positive bands localised at each side of the extended rDNA locus was observed in R. sphaerocarpa and R. raetam. The polymorphism revealed in our cytogenetic data allowed us to separate the group of R. raetam and R. monosperma from R. sphaerocarpa.

Karyotype characterization ofEpimediumspecies (Berberidaceae) by fluorescent banding and physical mapping of 45S and 5S rDNA

Epimedium is a very important economic genus not only for medicinal usage but also for horticul- ture. We used combined PI-DAPI (CPD) staining techniques and fl uorescent in situ hybridization (FISH) with 5S and 45S rDNA probes to investigate the karyotypic and cytogenetic chracteristics of Epimedium species. All the tested species had the same chromosome number 2n=2x=12 and the same karyotype asymmetry type 2A. Just one pair of satellite chromosomes were found in each Epimedium species. Two different karyotype formulae were identifi ed in the tested eight species. The CPD banding patterns varied among the eight Epimedium spe- cies. In the double-target FISH analysis, the 45S rDNA probe revealed the loci closely to the secondary constric- tions of satellite chromosome pair and 5S rDNA were located on the short arms of one metacentric pairs in the specimens. The present results provide the basis for the molecular genetics in Epimedium.

Karyotype analysis and polyploidy in Palaua and a comparison with its sister group Fuertesimalva (Malvaceae)

Abstract Palaua (Malveae, Malvaceae) comprises 15 species endemic to the hyperarid coastal desert of Chile and Peru. So far, chromosome counts have been known for two diploid species (2n= 2x= 10) only. Here we report new chromosome numbers for 12 species of Palaua and four of its sister group Fuertesimalva. Karyotypes including 4′,6′-diamidino-2-phenylindole dihydrochloride (DAPI)/chromomycin (CMA3) fluorescent banding are presented for selected species representative of each of the main clades of Palaua. An important finding is the discovery of polyploids in one exclusively tetraploid species (P. trisepala) and four species with mixed diploid and tetraploid cytotypes (P. dissecta, P. mollendoensis, P. moschata, and P. tomentosa). The diploid and tetraploid karyotypes are all unimodal, symmetrical and show one or two pairs of satellite chromosomes with their associated CMA+/DAPI− band depending on the cytotype. For some of the tetraploids an autopolyploid origin is suggested.

Chromosomal polymorphism in isolated populations of Elymus (Agropyron) in the Aegean:

Elymus rechingeri is a tetraploid (2n = 28) cross-fertilizer which grows in small isolated populations mainly on the Aegean islands. Chromosome morphology was studied in plants raised from seeds collected in nature and in plants resulting from inter- and intrapopulation crosses as well as selfing. Chromosomal polymorphism predominated in the material originating from nature and was observed both between and within populations. This polymorphism was expressed in the variable appearance of the three pairs of satellite chromosomes. The most common constitution of satellite chromosomes was found in Aegean and Egyptian materials and was considered to be the constitution characteristic of the species. Expected combinations of different types of satellite chromosomes were found in the offspring after inter- and intrapopulation crosses and after selfing. Some offspring plants also showed structural and numerical chromosome deviations. Fertility was lower in crosses between than within populations indicating genetical differences between populations. The karyotype of E. rechingeri shows great similarities to the karyotypes of E. furctus ssp. boreo-atlanticus (2n = 28) and E. striatulus (2n = 14). The genome formula J1J1J3J3 was suggested for E. rechingeri. Meiosis was generally normal but asynapsis and multivalent formation at metaphase I and separation difficulties at anaphase I were also encountered.

Broadening the Genetic Base of Soybean: A Multidisciplinary Approach

Soybean [Glycine max (L.) Merr.] is an economically important legume with 2n = 40 chromosomes, whose seeds contain an average of 40% protein and 20% oil, and its plants enrich the soil by fixing nitrogen in symbiosis with nitrogen-fixing bacteria. World soybean production has doubled in the past twenty years to over 220 million metric tons in 2006; the producing countries are U.S.A., Brazil, Argentina, China, and India. Soybean was domesticated in East Asia from its wild annual progenitor G. soja Sieb. & Zucc. (2n = 40). There are 26 wild perennial species, indigenous to Australia, of the subgenus Glycine but a common progenitor with 2n = 20 chromosomes has not been identified, and it may be extinct. It has been demonstrated that Glycine species are of either of allo-or auto-tetraploid origin. The cytogenetic knowledge of soybean lags far behind that of other model important crops (rice, maize, wheat, tomato), because it's somatic chromosomes are symmetrical, and only one pair of satellite chromosomes can be identified. Pachytene chromosome analysis created a chromosome map that has laid the foundation for producing primary trisomics. Several molecular linkage maps have been developed, but only 11 of the 20 molecular linkage groups (MLGs) have been associated with specific chromosomes. The genetic base of modern soybean cultivars is narrow and soybean breeders are confined to crossing within the primary gene pool (GP-1). Soybean does not have secondary gene pool (GP-2). Exploitation of the tertiary and quaternary gene pools (GP-3, GP-4) has been attempted but ended at the amphidiploid stage. A methodology for producing fertile lines derived from G. max and G. tomentella (2n = 78) cross has been developed, thereby making introgression of useful genes from GP-3. Genetic transformation has produced Roundup Ready® Soybeans, resistant to glyphosate herbicide.

Karyotype analysis and physical mapping of 45S rDNA in eight species of Sophora, Robinia, and Amorpha

The karyotype analysis and physical locations of 45S rDNA were carried out by means of fluorescence in situ hybridization in three species, and two forms of Sophora, two species of Robina, and one species of Amorpha. S. japonica L., S. japonica L. f. oligophylla Franch., S. japonica L. f. pendula Loud., and S. xanthantha C. Y. Ma. are all tetraploids with 2n = 28. There were four 45S rDNA sites in pericentromeric regions of two pairs of chromosomes in each of them. S. rubriflora Tsoong. is a triploid with 2n = 21, and three sites were located in each satellite of group 5 chromosomes. In R. pseudoacacia L. (2n = 2x = 22), we examined four intensive signals in telomeric regions of two pairs of satellite chromosomes. In R. hispida L. (2n = 2x = 30), there were four other signals in centromeric regions besides those like in R. pseudoacacia. Amorpha fruticosa L. has most chromosomes (2n = 40) among the eight materials, however, there were only six 45S rDNA loci and they laid in centromeric regions, and satellites of three pairs of chromosomes. 45S rDNA is a valuable chromosomal landmark in karyotype analysis. The distribution and genomic organization of rDNA in the three genera were also discussed.

New cytogenetic information on Allium iranicum (Alliaceae) from Iran

AbstractKaryotype analysis and chromosome behaviour in tetraploid Allium iranicum is reported. The somatic karyotype 2n = 32, consists of 12 pairs of metacentric chromosomes, two pairs of submetacentric chromosomes and two pairs of submetacentric satellite chromosomes. Chromosome complement follows two sets of 16 pairs of homologous chromosomes. A detailed analysis of Pachytene, Diplotene and Metaphase I of meiosis in pollen mother cells in this taxon showed that the most common chromosome configurations were bivalents at all subphases mentioned. It is concluded that A. iranicum is most likely a natural allotetraploid and certainly differs from related species A. ampeloprasum, A. commutatum and A. porrum.

한국 자생 붓꽃과 식물 5종의 핵형분석

한국 자생 붓꽃과 식물 5종 (노랑무늬붓꽃, 타래붓꽃, 연미붓꽃, 대청부채, 범부채)에 대한 핵형분석 보충 연구를 수행하였다. 5종의 염색체는 모두 이배체였으나 염색체 수와 핵형적 조성에 있어서는 종에 따라 차이를 나타냈다. 노랑무늬붓꽃의 핵형식은 2n=34=10m+16sm+8st로 2쌍의 부수체 염색체를, 타래붓꽃은 2n=40=26m+12sm十2st로 2쌍의 부수체 염색체를, 연미붓꽃은 2n=30=14m+16sm으로 5쌍의 부수체 염색체를, 대청부채는 2n=32=22m+10sm으로 2쌍의 부수체 염색체를, 범부채는 2n=32=20m+10sm+2st로 1쌍의 부수체 염색체를 포함하고 있었다. 본 연구 결과 이들 5종 식물에 대해 이전 핵형보고와는 다른 염색체 수와 부수체 염색체의 존재를 확인할 수 있었다. 이 결과는 각종의 세포유전학적 규명에 유용할 것으로 여겨지며, 또한 원예용 및 약용가치로 개발의 가치가 기대되는 붓꽃과 식물의 실용화 작업에 유용한 기초 자료가 되리라고 본다. A detailed karyotype analysis was carried out in five Korean native Iridaceae species; Iris pseudoacorus, I. pallasii. var. chinensis, I. tectrum, I. dichotoma and Belamcanda chinensis. Chromosome compositions of the five species showed that they have different karyotypic formulae; I. pseudoacorus 2n=34=10m+16smn+8st including two pairs of satellite chromosomes, I. pallasii var. chinensis 2n=40=26m+12sm+2st including two pairs of satellite chromosomes, I. tectrum 2n=30=14m+16sm including five pairs of satellite chromosomes, I. dichotoma 2n=32=22m+10sm including two pairs of satellite chromosomes, and B. chinensis 2n=32=20m+10sm+2st including one pair of satellite chromosomes. These results will supplement the previous cytogenetic reports in Iridaceae species and enhance our understanding on the genetic structure, which will be useful in clarifying the unique characteristics of each species for practical breeding programs for horticultural and pharmaceutical purposes.

Ribosomal RNA Gene Loci and Their Nucleolar Activity in Brassica alboglabra Bailey

Fluorescence in situ hybridization (FISH) and silver staining techniques were used to reveal the number, chromosomal sites and nucleolar activity of ribosomal RNA (rRNA) gene loci in Brassica alboglabra Bailey (genome: CC, 2n = 18). Two major and two minor rRNA gene loci were disclosed using FISH. The two major rRNA gene loci were located on the secondary constrictions of the satellited chromosome pair 9, the two minor rRNA gene loci, on the terminal region of the short arms of the non-satellited chromosome pair 8. Two silver-stained nucleolus organizer regions (Ag-NORs) were detected on the secondary constrictions of chromosome pair 9. Two major nucleoli were recorded in telophase nuclei. In interphase nuclei, two micronucleoli were observed in addition to the two major nuceoli. Thus, it is suggested that the satellited chromosome pair 9 with Ag-NORs contains major active rRNA gene loci leading to the formation of major nucleoli, while the non-satellited chromosome pair 8 without detectable Ag-NORs carries minor active rRNA gene loci responsible for the formation of micronucleoli.

Characterization of chromosomes and genome organization of Thapsia garganica L. by localizations of rRNA genes using fluorescent in situ hybridization.

The karyotype (2n = 22) of Thapsia garganica L. (Apiaceae, Apioideae, Laserpitieae) was constructed using molecular cytogenetics. The size of the 22 chromosomes ranged between 5 and 10 microns. Two chromosomes had satellites on the short arms. The 18S-5.8S-26S rDNA genes were located to the two satellites by fluorescent in situ hybridization (FISH). The 5S rDNA repeat unit was amplified and located by FISH to one pair of the non-satellited chromosomes. Sequencing 5S rDNA of T. garganica revealed two classes of genes based on distinct intergenic spacer regions of 191/193-bp and 181-bp. respectively. The ITS1 and ITS2 of the 18S-5.8S-26S repeats were also amplified and phylogenetic analysis placed T. garganica in a distinct clade from the Daucus clade containing Laserpitium sp. The organization of T. garganica L. genome is tentatively divided in group A of 14 chromosomes with median centromere and of which one pair (q/p 1.22) contains single 5S rDNA locus on the long arm. Group B consists of six chromosomes with subterminal centromeres (q/p between 4.23 and 7.92) and finally group C with the satellited chromosome pair containing the 18S-5.8S-26S rDNA locus at the secondary constriction.