Somatic Chromosome Number Of 2n Research Articles

Chromosome diversity and evolution in Allium (Allioideae, Amaryllidaceae)

Despite extensive literature on the diversity of karyotypes in Allium is available, no attempt to analyse these data together, within a robust phylogenetic framework, has been carried out so far. Thus, we examined patterns and trends in chromosome evolution across the genus. Based on literature survey, karyo-morphometric features for 207 species belonging to 12 subgenera of Allium were obtained. Included in the data-set were basic chromosome number (x), somatic chromosome number (2n), total haploid (monoploid) chromosome length (THL) and three different measures defining karyotype structure: CVCI, measuring how heterogeneous are centromeres positions in a karyotype, CVCL and MCA, quantifying interchromosomal and intrachromosomal karyotype asymmetry, respectively. Trends in karyotype evolution were analysed by phylogenetic regressions and independent contrasts. Mean karyotypes highlighted differences and similarities in karyotype structure between the 12 subgenera. Further differences were noted when the two parameters for analysing karyotype asymmetry were assessed. In addition, by examining the effects of increasing karyotype dimensions (a proxy for genome size) on karyotype structure and asymmetry, it was shown that in Allium species, the DNA was added proportionally to their arm lengths. Overall, p = 8 and somehow intermediate karyotype asymmetry levels seem to represent plesiomorphic character-states in Allium.

New chromosome number counts and karyotype analyses in three important genera of Zingiberaceae

Zingiberaceae has reportedly undergone frequent polyploidization and hybridization events. Here we describe the new chromosome counts and karyomorphological details for the three important members of the family. Root tip cells of plants of Alpinia zerumbet (earlier reported to be 2n = 48, 40) and Globba marantina (reportedly 2n = 44 to 2n = 96) showed 2n = 52 chromosomes, both being aneuploids, Hedychium spicatum plants (2n = 34 according to previous reports) were found to be tetraploid with somatic chromosome number of 2n = 68. Detailed karyomorphological analyses performed using various parameters revealed that all the three novel cytotypes had moderately symmetrical karyotypes with low levels of intra– and interchromosomal variation in terms of both chromosome lengths and centromeric indices.

An expansion of the genus Deinostigma (Gesneriaceae)

Based on molecular, morphological and cytological studies the previously monotypic genus Deinostigma W.T.Wang & Z.Y.Li has been expanded to include several species previously ascribed to Primulina Hance. Deinostigma now comprises seven species, including one previously placed in synonymy. The new combinations Deinostigma cicatricosa (W.T.Wang) D.J.Middleton & Mich.Moller, Deinostigma cycnostyla (B.L.Burtt) D.J.Middleton & H.J.Atkins, Deinostigma cyrtocarpa (D.Fang & L.Zeng) Mich.Moller & H.J.Atkins, Deinostigma eberhardtii (Pellegr.) D.J.Middleton & H.J.Atkins, Deinostigma minutihamata (D.Wood) D.J.Middleton & H.J.Atkins and Deinostigma tamiana (B.L.Burtt) D.J.Middleton & H.J.Atkins are made. Deinostigma eberhardtii is lectotypified. The genus is defined by a combination of an alternate leaf arrangement, hooked hairs on many plant parts, flowers with the pedicel inserted at an angle and off-centre on the receptacle, and, where known, a somatic chromosome number (2n) of < 36. This new circumscription of the genus expands its distribution from Vietnam into South China.

Karyotype Analysis and 4C Nuclear DNA Estimation in Different Cultivars of &lt;i&gt;Clitoria ternatea&lt;/i&gt; L.

The present article has reported a detailed karyotype analysis and 4C nuclear DNA estimation in different cultivars and populations of Clitoria ternatea L. of Fabaceae. This plant, widely distributed in tropical regions in India, is a climber and is an economically important medicinal plant. The karyotype study has revealed a constancy in the diploid somatic chromosome number (2n=16) in all these cultivars and populations. However, the nature and number of nucleolar chromosomes varied. The centromeric chromosomes were either metacentric or sub-metacentric in all these cultivars. The total chromosome length and volume differed among these cultivars and populations having the same somatic chromosome number. The differential condensation of chromosomes and the association of variable amounts of proteins in chromosome composition might have been responsible for such differences. In situ cytophotometric studies revealed an intermediate genome size in this species. This is the first report on the detailed karyotype and genome size of cultivars of Clitoria ternatea L.

Further observations on chromosome diversity analysis in wild species of Vigna from India

Ten wild species of Vigna from the Indian gene centre have been karyo-morphologically analysed. All the studied taxa had somatic chromosome number of 2n = 22 except V. glabrescens which had 2n = 44. The chromosomes were found to be either metacentric, submetacentric and subtelocentric in type with their respective chromosome complements, and the complete absence of telocentric chromosomes in all of the taxa studied. The karyotypes of the species were mostly symmetrical. The significance of karyotypic variation among wild species in comparison with the cultivated ones of the genus Vigna has been discussed in detail. Such information has value in understanding cytogenetical relationship amongst these wild species reported to comprise of genes for resistance to insect, pests and diseases.

Cytogenetical treatise of Indian representative species of Cucumis. A karyotypic approach

Karyomorphological studies have been carried out in nine species and five varieties of the genus Cucumis representing Indian gene pool. The present investigations reveal the occurrence of two somatic chromosome numbers 2n = 14, 24 in the genus. C. ritchiei and C. indicus the two new species, were found to be having somatic chromosome numbers of 2n = 24 and 2n = 20 respectively. The wild species viz. C. hystrix, C. setosus, C. prophetarum, C. dipsaceus, C. indicus have very less number of median-centromeric chromosomes, high asymmetry indices, while melon groups have intermediate number of median -centromeric chromosomes. C. sativus, C. callosus, C. ritchiei show lesser number median-cen-tromeric chromosomes and very less asymmetry indices. The importance of karyotypic variation with respect to speciation within the genus Cucumis have been discussed.

Allium kyrenium (Amaryllidaceae), a new species from Northern Cyprus

Allium kyrenium, a new species of Allium sect. Codonoprasum, is described and illustrated from northern Cyprus. It is a very circumscribed geophyte growing on the calcareous cliffs of the Kyrenia range. This diploid species, with a somatic chromosome number 2n = 16, shows close morphological relationships with A. stamineum, a species complex distributed in the eastern Mediterranean area. Its morphology, karyology, leaf anatomy, ecology, conservation status and taxonomical relationships with the allied species belonging to the A. stamineum group are examined.

A new species of Trigonella sect. Ellipticae (Leguminosae-Papilionoideae) from Iran, including cytogenetic and anatomical notes

A new species, Trigonella bakhtiarica, from the Iranian province Chahar Mahal Va Bakhtiari is described, illustrated and compared to its most closely related species, T. aphanoneura. Trigonella bakhtiarica has a longer corolla and differs in the shape, surface and size of its pods, which are taxonomically informative characters in Trigonella sect. Ellipticae. Chromosome counts and meiosis assays show that both species are diploid, and that their euploid plants possess a somatic chromosome number of 2n = 2x = 16, which is consistent with the predicted base number of x = 8.

Badania kariologiczne nad dwoma gatunkami rodzaju Sparganium L. [Karyological studies in two species of the genus Sparganium

The somatic chromosome numbers 2n = 30 for &lt;em&gt;Sparganium neglectum&lt;/em&gt; and &lt;em&gt;S. minimum&lt;/em&gt; was established. The karyotype of the first species consist of 8 iso- and 7 heterobronchial chromosomes and the reverse is true for the second species. In metabolic nuclei 30 chromocentres are visible.

NEW CHROMOSOME COUNTS OF BERBERIS L. (BERBERIDACEAE) SUGGEST THAT POLYPLOIDY DOES NOT PLAY A SIGNIFICANT ROLE IN THE DIVERSIFICATION OF THE GENUS IN THE NEPAL HIMALAYA

Chromosomes were counted for nine of the 24 taxa of Berberis (Berberidaceae) from Nepal, five of which were counted for the first time. The results show that all these species have somatic chromosome numbers of 2n = 28. The absence of polyploids suggests that polyploidy may not have been a major driver of speciation and diversification of Berberis in the Nepal Himalaya.

Begonia jinyunensis (Begoniaceae, section Platycentrum), a new palmately compound leaved species from Chongqing, China.

BackgroundContinental China is the center of Begonia species diversity in Asia and contains more than 60 species out of about 110 named species of section Platycentrum. Mt. Jinyun, located in Chongqing City at the upper reaches of the Yangtze River, harbors a subtropical broadleaved forest with high species diversity. During a botanical survey in Mt. Jinyun, an unknown Begonia species of sect. Platycentrum with palmately compound leaves was collected and studied based on detailed morphological observations and cytological and molecular phylogenetic analyses.ResultsThe unknown Begonia bears a superficial resemblance to B. hemsleyana in having palmately compound leaves, a feature unseen in other species of sect. Platycentrum in China. It is however sharply distinct from the latter in the acaulous habit with aerial stems seen only at anthesis and long rhizomes (vs. erect stems to 70 cm or taller with short rhizomes), 4–6 pinnatilobed leaflets with indistinct, decurrent petiolules (vs. 7–10 serrate leaflets with distinct petiolules), and white (vs. pink) tepals. Molecular phylogenetic analyses based on nuclear ribosomal DNA and chloroplast DNA sequences indicated that this species was allied to Platycentrum species occurring in Southwest and South-central China and Vietnam, including B. hemsleyana, and clearly separable from these species. Somatic chromosome number of 2n = 22 was reported for this unknown species. The diploid chromosome number is agreeable with those published for Begonia sect. Platycentrum.ConclusionsThe unknown Begonia is confirmed to be a new species of sect. Platycentrum and hereto described as Begonia jinyunensis C.-I Peng, B. Ding & Q. Wang.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-014-0062-6) contains supplementary material, which is available to authorized users.

Physical localization of rRNA genes by fluorescence in situ hybridization (FISH) and analysis of spacer length variants of 45S rRNA (slvs) genes in some species of genus Sesbania

The somatic chromosome numbers 2n = 12 in S. macrantha, S. coerulescens and 2n = 24 in S. simplicuscula were determined, additionally the contradictory chromosome numbers of S. bispinosa (2n = 12, 13, 14, 24) and S. pachycarpa (2n 12, 14) were determined as 2n = 24 and 2n = 14, respectively. The number of 5S rDNA sites in chromosome pair 1 was highly conserved in all the diploid and tetraploid species studied irrespective of their geographic distribution, suggesting that all diploid and tetraploid species/cytotypes of Sesbania analyzed in the present study are in close proximity. Cytogenetic mapping of the 45S multi-gene family was also carried out using fluorescence in situ hybridization. 45S rDNA was consistently located on short or long arms of two sub-metacentric chromosome pairs except on one chromosome pair in S. macrantha and on three chromosome pairs in S. bispinosa and S. cannabina. Out of these nine species, we observed the homogenization of intergenic spacer in six species and find only one spacer length variant (slv) located on one to three chromosome loci. However, three of the species were observed to have two slvs located on two different chromosomes. The species were grouped as per their evolutionary relationship on the basis of the results of the present study.

Persicaria wugongshanensis (Polygonaceae: Persicarieae), an odoriferous and distylous new species from Jiangxi, eastern China

Persicaria wugongshanensis, a new species from Wugongshan Mountain, Jiangxi Province in eastern China, is described and illustrated. The new species is a distinctively odoriferous herb characterized by having glandular leaves and tepals, stout inflorescences, dimorphic flowers, extraordinarily long pedicels and densely pitted achenes. A morphological comparison among the new species and its putative relatives, P. hydropiper, P. japonica, P. jucunda and P. odorata, is presented. Comparative micromorphological characters of achenes, leaves, pollen grains and tepals of the new species and its closest relative P. odorata were also presented. Distyly and its ancillary dimorphism were observed and described. The somatic chromosome number (2n = 20) and karyotype formula (2n = 14 m + 6 sm) of the new species were reported.

Natural hybrids between Tragopogon mirus and T. miscellus (Asteraceae): A new perspective on karyotypic changes following hybridization at the polyploid level

Natural hybrids have formed in Pullman, Washington, United States between the recently formed allotetraploids Tragopogon miscellus and T. mirus. In addition to forming spontaneously, these hybrids are semifertile, propagating via achenes. Previous work indicated that the tetraploid hybrids have genetic contributions from three progenitor diploids: T. dubius, T. pratensis, and T. porrifolius. Because the hybrids contain genomes from three species, they should be karyotypically variable and have very low fertility. To better understand how these hybrids are semifertile, we applied fluorescent probes to determine chromosome composition. • We sequentially conducted fluorescence and genomic in situ hybridization to generate karyotypes for five hybrid individuals grown from field-collected achenes. • All plants had the expected somatic chromosome number (2n = 24), but none showed an additive F1 chromosome complement, i.e., two sets of chromosomes from T. dubius and one set of chromosomes each from T. porrifolius and T. pratensis. No individuals shared an identical karyotype, but chromosomal variation followed a compensatory pattern of substitutions, with all groups of putatively homeologous chromosomes consistently totaling four. • The hybrids appear to be shifting away from a parentally additive F1 karyotype to chromosomal compositions that are mostly, or entirely, disomic. We hypothesize that this process may eventually lead to the elimination of chromosomes from a population and produce a stabilized karyotype distinct from both allotetraploid parents. This work has implications for other hybrids formed between polyploids, in that they may be hard to detect using sequence data alone due to multilateral patterns of chromosome elimination.

Karyological studies of 10 Cirsium sect. Epitrachys (Asteraceae) species from Turkey

Detailed karyotype properties were established for 10 Cirsium Mill. sect. Epitrachys DC. species distributed in Turkey. The species Cirsium ligulare Boiss., C. sintenisii Freyn, C. boluense P.H.Davis & Parris, C. eriophorum (L.) Scop., C. steirolepis Petr., C. baytopae P.H.Davis & Parris, C. poluninii P.H.Davis & Parris, C. ciliatum (Murray) Moench subsp. szovitsii (K.Koch) Petr., C. ellenbergii Bornm., and C. vulgare (Savi) Ten. have the somatic chromosome number 2n = 2x = 34, whereas C. sintenisii and C. vulgare showed 2n = 4x = 68. The chromosome numbers of C. sintenisii, C. boluense, C. baytopae, C. poluninii, and C. ellenbergii are newly reported here. Karyotype analysis indicated that chromosomes of Cirsium taxa generally have median region (m) and rarely median point (M) and submedian region (sm) karyotypes. The findings for each of the analyzed taxa are compared with the results of previous studies.

Comparative karyomorphological study of some Indian Cymbidium Swartz, 1799 (Cymbidieae, Orchidaceae)

Understanding the genetic resources and diversity is very important for the breeding programs and improvement of several economically important orchids like Cymbidium. Karyomorphological studies have been carried out on seven Cymbidium species, Cymbidium aloifolium (Linnaeus, 1753), Cymbidium devonianum Paxton,1843, Cymbidium elegans Lindley, 1828, Cymbidium iridioides D. Don, 1825, Cymbidium lowianum Rchb. f.,1877, Cymbidium tigrinum Parish ex Hook. f., 1864, and Cymbidium tracyanum L. Castle,1890, most of them endangered/threatened in their natural habitat. As reported earlier, the somatic chromosome number (2n = 40) has been observed in all the seven species. Distinct inter-specific variation was recorded in the arm ratio of few homologous pairs in the complements. Symmetrical or almost symmetrical karyotypes were prevalent; however significant asymmetry was reported in Cymbidium iridioides and Cymbidium tracyanum. The significance of karyotypic variation in speciation of the genus Cymbidium has been discussed. This study provides useful chromosome landmarks and evidence about genome evolution, heteromorphic chromosomes based heterozygosity, basic chromosome number and ploidy level in the genus Cymbidium.

Karyomorphological Studies in Some Species of Parnassia L. (Saxifragaceae s.l.) in East Asia and Intraspecific Polyploidy of P. palustris L.

Karyomorphological information is one of the most important characters for cytotaxonomy. We described karyomorphology of 14 species of Parnassia in East Asia. They had commonly the resting chromosomes of the simple chromocenter type and the mitotic prophase chromosomes of the proximal type. The somatic chromosome number of 2n=14 was shown in three species, that of 2n=18 was shown in six species, that of 2n=18 or 36 was shown in two species, that of 2n=32 was shown in one species, that of 2n=36 or 36+1∼8 s was shown in one species, and that of 2n=18, 27, 36 or 45 was shown in one species. They were commonly monomodal (gradual) decrease in length from the largest to the smallest chromosomes. However, their absolute chromosome sizes were different from each other. Average chromosome sizes were recognized as three types small (1.21 μm), medium (1.7–2.36 μm), and large (3.1–3.75 μm). Parnassia palustris showed four cytotypes that could be likely cytogeographically correlated with habitats, polyploidy, and sizes of pollen grains.

Karyology of the genus Faberia (Cichorieae–Asteraceae) and its systematic implications

Faberia Hemsl., a small genus of six species in the tribe Cichorieae, Asteraceae, has been karyologically investigated for the first time. All four studied species were revealed to have the somatic chromosome number 2n = 34, and thus the basic number of the genus was assumed to be x = 17. This rather high basic number has been previously reported very rarely in the tribe, occurring otherwise only in Warionia Benth. &amp; Coss., a monospecific genus endemic to northwestern Africa, and in the American species of Lactuca L. The chromosome morphology was very similar among the four species, with the majority being median centromeric (m) and a few submedian centromeric (sm). In all the karyotypes the chromosomes were medium‐sized (6.33–1.61 μm), and showed a steady gradation in length from the longest to the shortest, with no evidence of bimodality. Our results strongly support the recognition of Faberia as an independent genus and the inclusion of Faberiopsis Shih &amp; Y. L. Chen in Faberia.

Chromosome studies in four species of Saxifraga L. (Saxifragaceae) collected in Tuva and adjacent regions, Russia

Four species of Saxifraga such as S. aestivalis, S. hieracifolia, S. foliolosa and S. hirculus were collected in Russia and observed their somatic chromosome numbers. Saxifraga aestivalis showed the somatic chromosome number of 2n=28, S. hieracifolia showed that of 2n=114, S. foliolosa showed that of 2n=60, and S. hirculus showed that of 2n=16. These chromosome numbers verifi ed with the previous reports, expect for S. foliolosa. The chromosome numbers of 2n=60 for S. foliolosa was reported here for the fi rst time. Chromosome sizes of four species varied in mean lengths with each others; S. aestivalis and S. foliolosa had small-sized mean chromosomes 1.31 μm and 1.47 μm long respectively, S. hieracifolia had medium sized, mean chromosome 2.75 μm long, and S. hirculus had large sized, mean chromosome 4.4 μm long. Saxifraga aestivalis had a bi-modality and decrease in chromosome size from the largest to the smallest chromosomes, while the other three species had mono-modal or gradual decrease in chromosome size from the largest to the smallest chromosomes.

Cardiospermum cristobaliae (Sapindaceae, Paullinieae), una nueva especie de Minas Gerais, Brasil

Fil: Ferrucci, Maria Silvia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Nordeste. Instituto de Botanica del Nordeste (i); Argentina. Universidad Nacional del Nordeste; Argentina